I tend to prefer painting a different mini each time rather than chain painting the whole set. Anyone knows how to fix that?

So I started quite recently and working on minis on a regular though not frequent basis.

I really enjoy painting and I can spend several hours on one mini to make it look great. (As great as it gets considering my current skill).

I'm currently working on the minis from HeroQuest and as much as I like painting them, I'm a bit reluctant to start the goblins/orcs because there are so "many" of them. I'd rather have only different ones to paint.

Several questions:

Any tips on improving this?

Also, if I don't manage to "fix" this, are there existing sets (or even games) with a lot of different minis?