The sketches in the Monster Manual index are cute, but I'm not sure what all of them are.
1. A bulette surprising a shepherd and two goats.
2. A troll searching for its nearby severed head.
3. A medium-sized gold (?) dragon sitting on a prone woman.
4. An adventurer poking a flumph with a ten foot pole.
5. An animated rug attacking someone by wrapping them up.
6. A minotaur looking over a man's shoulder at a parchment, presumably a map.
7. A man (Mirt the Moneylender?) looking at his nude doppleganger (?) in a bush.
8. An otyugh under an outhouse.