My pick would be a game called Firepower.
Top-down tank game. One of the first amiga games I played at a mates house, split screen. Not sure how it fares single player - but multiplayer this was the shiznitz.
As for Lionheart, as mentioned by adamst85 - that was way famous. (unless your not talking about the Thalion version)
Actually Leander was famous too (don't think it sold well though) as it was made by Psygnosis. (loads of add's for that in mags)
Also considering lot's of add's... Elf, by Ocean was also well advertised.