Crayola do some crayons and paints for 18 months +.
They're around £5 per pack but are nice and chunky for younger ones, are nicely shaped and are a "no mess" type of thing.
I still use them now with my 2 yr old as they're less messy!
I think they're called Crayola beginnings Tadoodles. Toys r us have them :)
In terms of other activities, I've just started going to more 'groups' with my little one. There's things like Jungle Jingles (singing / drama), a baby / toddler gym which they can attend once walking, tots on ice which again is for when they're walking. Even though everything only lasts about an hour or so, I try to do about 3-4 outside activities with him each week to give us a break from the home scene.
Even though it's cold, we also do spur of the moment things when he's looking a bit bored like putting on wellies and just going for a splash in the puddles right outside the house. In the summer we went barefoot in the rain which was fun! I also bring the outdoors indoors - the water / sand table comes inside and I set it up occasionally. A spur of the moment bath which lasts until they're bored of it.
Otherwise, lots of singing (especially action songs), dancing, cuddles, tickles, crawling around acting silly. Someone will shoot me but Mr Tumble is very educational. I think my ds loved teletubbies at 12 months though (although not really educational).
You can also encourage physical exercise in the home. I taught mine to do roly polys (obviously with me supporting him), running on the spot, reacting to commands such as "stand up, sit down, turn around, nod your head" which is still a favourite game.
Now my minds gone blank... hope that gives some ideas anyway :)