I am aware this has already been brought up a bunch, but I want to redo the suggestion since the last one I have seen on the forums was back from December 2019. EHEM.
So, I think Guild’s are somewhat bland as of current. I think that guilds, first off, should have a set Guild Base, that, when people try to enter, they can search a registered Guild name, can enter the respective Guild base. That said Guild base can be edited to the Guild’s liking, but the main things that stay put are a custom Guild Messages board that only guild leaders can edit, a team editor, and a guild exclusive storage for items and money, which has two primary parts: The Main Guild Storage and the Leader Storage. Each of which are self explanatory. One can be accessed by all of the guild and one only by guild leaders. The bank however can be only accessed by guild leaders but can be donated to by anyone in the guild. Each of these bases would be stationed in the major regions towns, like Grassroot for example.
The second thing I want to see in guilds are a kind of boost system. Like if you pay a certain amount of money to a NPC (Like Victini) at a prize wheel outside of the Guild Base, you can get a special boost for a limited amount of time to your entire guild (say for 24hrs) which is like an EXP Boost or a boosted chance to find shinies.
My last thing to add is maybe a guild raid system. Every few hours, in a certain dungeon, there can be a raid with lots of pokemon to defeat. The whole guild can go together (instead of just 4) to beat the raid and earn “Guild Raid Points” which can be spent at a guild shop for special guild items.
So, uh, tell me what you think ^^