@BarrierWithAshes Mobygames has a massive database of games with enough metadata to be a good trick for obscure queries like this. Not perfect (I guess cataloguing metadata on every game ever made is complicated?), but good enough to give some plausible leads if you want to dig a bit. For example I see that there's a Banjo Kazooie GBA game that looks like it might be up your alley.
Link to "isometric platformers", since it doesn't seem to have a collectathon genre tag: