I am ttc so no direct experience yet, and am struggling for present ideas for small people esp after using up all my ideas this Christmas, and have three birthdays in next few weeks...
Have six to buy for in total, two boys (both 2) and four girls (0 - 8). I had a list of 'Good Ideas' and tend to stock up during the year whenever I see something I think would be good for one or another, but am rapidly running out of ideas... have asked parents and had a few suggestions but some are over budget (around £10-15 each) and others are hard to get on short notice.
Original list of ideas (very limited!):
Dressing up outfits
Clothes etc (ok, more for parents than fun for kids)
Lego/Duplo/Brio etc
Soft toys
Jigsaws/puzzles
'Making stuff' kits e.g. beads for bracelets, paint models etc
...
This list has worn a bit thin over the years esp where there are siblings and they both get variations of the same thing. Am happy in 'cool auntie' role but feel I fall down a bit at presents 
I am usually ok at finding something for the girls but really struggle for the boys, don't know if it's gender/temperament (both are little monsters! So have been told not to buy anything that can cause damage, so that's a lot of toys ruled out) more than age, but just not been good at finding stuff that 2yr old boys will like that doesn't require 100% adult input, whereas 2yr old girls seemed happy to play with various dolls/outfits... tried this for boys and heard later that they were appreciated by the parents but not the children
So any ideas within budget appreciated! Also if you can say where to get them from and what they should cost - spent a lot more on one toy at Christmas than I 'should' have, apparently, should have bought off Amazon rather than Toys R Us...