Thank you for this thread. 
The first picture is our kitten-sized Corby, who barely tolerated myself and my daughter - but absolutely adored my son (who was born when she was 6 years old). She would have gone to the ends of the earth and back for him, quite frankly, and I credit her with saving his life before he was even born (I miscarried his twin, and was awoken by a frantic cat headbutting me - I'd not known what was going on. I was 9 weeks pregnant at the time). She was 18 when she passed, of heart complications that we didn't know she had. It sort of broke my son for a while. So, she's the tuxedo cat sunning herself (and glowering at me for daring to take the photo!), and behind her is Hermes, aka Mimi. He was 3 when he passed from a build up of calcium in his urethra - apparently a very common thing for neutered tom-cats! He was part Bengal, and twin to the cat who is still with us (called Hercules), but he was also the bitchiest little diva I've ever known! If our dog was barking, Mimi would stalk - not even stroll, or swagger, but stalk - up to him, claws clicking on the floorboards, and slap the dog. Consequently our springer was absolutely terrified of him! Our lovely vet tried his hardest to save him, and only realised once they'd opened him up that it wasn't going to be possible (they were talking at one point about changing him from a tom- to a queen, which I didn't even know was possible at the time), so I went rushing down there to be with him when he passed. He'd sort of come round a little from the sedation as the vet's nurse took me into the back room where they kennel their patients, and as soon as he heard my voice, this little head popped up, very blearily peering for me, and he started to call - it was as if he were saying "Mama's here to take me home!". When he passed, the nurse and I were both in floods of tears. That was 10 years ago now, and I still think I can hear him clicking along the hallway. He also pee'd on my foot when he was a kitten, as I was lying on my son's bed, reading to him before he went to sleep - Mimi wanted his supper, and he was furious that I was still reading as opposed to feeding him.
The second picture is of my Carma, aka "Psycho". He was almost 22 when he died, and had been in my life since the age of 3 weeks old. He saw me through university, a relationship, 2 children growing up, career, disablity, major depression, and PTSD. He slept on my head at night, because during those first few weeks with him, the only way I could get him to sleep was by letting him curl up in the crook of my neck/shoulder and him suckling on my earlobe. He thought he could fly at the age of 6 weeks old, jumped out of my first floor kitchen window, straight onto solid concrete - and realised he couldn't get back home again. So he kicked our downstairs neighbours rabbit out of its hutch and hid inside there, until he heard me frantically calling his name. He'd herd my daughter to me if I called her name 3 times, and she was ignoring me (claws out, swiping through the air at her legs, tail lashing), hated my (now ex) partner with a passion, thought he'd hatched my son, because he used to drape himself across my bump and purr every time my son kicked or moved (for about a year after my son was born, if he started to grizzle in his cot, Carma would position himself nearby and purr - and my son would drift off to sleep). When I woke in the middle of the night from nightmares, he'd lazily start to purr and let me drape his belly fur across my eyes - then keep purring until I went back to sleep, like a lullaby. He went missing for 3 days and my entire street, bar one neighbour, searched for him. An indoor cat since the rabbit/super-cat incident, Carma had wandered out of the front door when my daughter was putting the recycling out - later, I'd heard an imperious meow, but thought he was upstairs, not waiting on the doorstep for me to let him back inside. The one neighbour who hadn't joined in with the search had locked him into her utility cupboard by the front door, thinking he was a pregnant queen (I suspect she saw £ signs flashing before her eyes - she's a nasty woman at the best of times!), and it was only when another neighbour's small daughter mentioned this in her hearing that he was rescued. Bugger had heard me calling for him, and decided to ignore me, just as he perceived I'd ignored his demand for the door to be opened! He had FD and would often forget he'd been fed, and he was stubborn beyond belief. He hung on until I'd come to terms with his death, I think, but on that last day, he just wanted to be held by me - when my son took him so that he and my daughter could say "goodbye", he cried and struggled to get back to me. So I spent most of the day, waiting for the end of the vet's surgery, with him curled up in my arms with one paw hooked into my jumper as though he were trying to cuddle me, too. And we spent a fair amount of the day sitting outside in the garden discussing what rose bush we were going to plant where, even though I knew he wouldn't get to sit out in the sunny back yard with me ever again. That was March 2019, so it's been a little over a year now, but I will always miss him. He just got too tired to go on, really.
And the last photo is of Merlin, or 'Mog', who died last week (July 21st) of what we think was a brain tumour. His death was ridiculously unexpected - although in hindsight, there were little indicators that it was coming which we, not knowing, just thought "oh, that was odd!". Merlin was my son's first birthday gift - he was the last kitten left from its litter in the pet shop, and his yowling could be heard from outside. He was "too noisy", apparently, so no one wanted him. My ex felt sorry for him, so home he came (he'd popped in to get some fish food and left with a kitten...). At home, he was too quiet - he'd fall asleep on the sofa in a pile of my children's stuffed toys, and one of us would sit on him, not having seen/heard him. He went bald from his waist downwards due to stress, following our move/relationship breakdown, and Mimi had a strange fascination with stalking him around the house, which didn't help. He was grumpy, and looked evil, but he was the softest, sweetest of cats whose favourite place in the world was... wherever my daughter was. Gradually he became her cat, and wherever she was sat, he was either on her lap, tucked under her long hair (I always used to joke that he'd probably adore a wig of his own!), on top of her when she was in bed, or next to her... with one foot always touching her. He also adored cheese. I swear, I could open a new packet in the kitchen, and wherever he was, he'd hear it. Just the cheese, mind, not anything else. But there'd be a THUMP as he rolled off of my daughter's bed, or chair, and then loud thudding as he hurtled down the stairs, and suddenly I'd have a pleading cat next to me! He hated heat, because it made him itchy, but he loved our fire - I think the flickering of the flames soothed him, somehow - and on Monday, he strangely insisted he was sleeping on the sofa, stretched out "like a lion", in front of the not-lit fire. The vet said the next day that he must have had a huge stroke during the night, given that he was staggering around like he'd drunk a gallon of wine, or forgotten how many legs he had. We were fortunate in that both of my children were allowed into the consulting room to say "goodbye" to him - and I'm grateful that he had the stroke, or aneurysm, which actually killed him, literally as soon as they'd left the room. He - like Mimi, and Corby, and Carma (and our elderly spaniel who died last Halloween) before him - passed in my arms, being told how very loved he was, and always will be, by us. At the moment, my daughter's not coping very well with his loss - exacerbated by the fact that her boyfriend of 4 years, the man she'd intended on marrying/having a family of her own with, dumped her that night. Normally, it'd be Merlin dealing with tears, and upset, and everything else that their break-ups involved (she says this is the last time, because he knew about Merlin, then callously said "it's over"...), and she admits that she feels like she's lost a limb, but she's also grateful for having been furloughed, so that she got to spend precious time with her beloved Mog.
Our last cat, Hercules, thinks he's a dog, and is very much my 16 year old son's cat. He's 14 now and is technically a geriatric... who is obviously enjoying a second kitten-hood, given that he stays up late, gets up late, swaggers about as if he owns the place, yowls back when he's told that he doesn't... and inhales his food rather than taste it. He adores my 3 year old dog, Littlun, though, and they're about the same height (Hercules is also part-Bengal and is "a big boy" to quote my son), so when he wants to cuddle her, she gets little choice in the matter. Yesterday, though, he licked her nose. Which was sweet.