My childhood favourite is Gogo the Ghost for the C64. The title melody still lives rent free in my head some 40 years later. It's still kinda fun to play.
https://www.youtube.com/watch?v=BAnPjDd9N88
I can also recommend the Berks games for the C16, especially Berks 3. The original programmer even released a fourth game a few years back. If you want to give those games a try, you could skip 3 and play 4 instead. 4 has the levels from 3 as part of the campaign.
https://www.youtube.com/watch?v=Ry6IlcQuwEQ