What units to use as games goes on

[rollems]

hi all.

i am new to game but getting hang of it and really enjoying it. i was curious what units do you guys get or suggest to get while the game goes on.

i am currently having.
2 Archmages , 34 royal snakes , 1 royal throne , 15 polar bear , 15 droids.
8 black nights ( cant get more currently )
just unlocked Rusty anchor.

so what army would you suggest me to get.

is there a list which says what to get/drop while games progresses ?