There was a hilarious illustrated book "Greek to Me". It is a thorough (English) introduction to koine Greek, mainly Bible as well as classical from Herodotus, Arrian, et al.

It uses the silly-picture mnemonic approach. For instance, the verb εγειρω features a fellow raising up a suction-cup arrow with an egg stuck in it.

Present-indicative conjugations are in a picture of an omelet oozing in an oasis:

-ω -ομεν

-εις -ετε

-ει -ουσιν