stats.txt

Original discord.py:

Member      184484
User        154373
KeyedRef    154223
_Overwrites 149067
list        88968
Colour      74905
Role        74745
Permissions 74745
TextChannel 52258
Emoji       36466


After stripping some fields, notably colour from role:

Member       184135
User         154029
KeyedRef     153928
_Overwrites  149019
list         88201 
Role         74734 
TextChannel  52252 
Emoji        36469 
VoiceChannel 17604 
dict         14059 


After stripping custom emoji support:

Member          184042
User            153974
KeyedRef        153862
_Overwrites     149018
list            91870
Role            74734
TextChannel     52251
VoiceChannel    17604
dict            14058
CategoryChannel 12387

After using a weakrefdict to store members

_Overwrites     152474
list            95298
Role            76122
TextChannel     53273
function        26504
dict            22046
VoiceChannel    17799
tuple           15181
CategoryChannel 12570
weakref         7043
(on startup, number of member objects expected to grow over time)