I use Hyaluronic Acid, Buffet, Caffeine and the gentle Ascorbyl Tetraisopalmitate Solution 20% in Vitamin F
I like all of them. Previously, I'd only used Aveeno moisturiser, avoiding everything else as I have eczema prone, sensitive skin. My skin drank up the HA in particular even I started as I think it was actually more dehydrated than dry. However, I'm waiting for my order of Hadalabo Gokujun premium hyaluronic solution 170ml (approx £10) as many have recommended and it's less than half price of TO's.
Notes: Niacinamide+Zinc seems to be a Marmite product, some love it, makes others have worse breakouts.
Buffet: seems to cause whiteheads in some, but most love it.
Azelaic Acid seems a really good product.
Ppl go mad and buy everything as it's cheap, without having the first clue of how to use, frequency etc. Then they complain it's making their skin worse! Everything needs introducing slowly, so any effects can be monitored.
Ppl seem to feel the need to buy the strongest options of products, so they'll buy the stronger 23% Vit C, when more gentle options are available. Same with retinoids - and want to use them every day and are then surprised when their skin reacts badly.
Lots of info on the Victoria Health website in their Ordinary section, loads of videos on YouTube, esp Gothamista. FB group The Ordinary Chat Room is worth joining, great advice from contributors who know their stuff and info in Files section.