Mapper
Almost nobody likes this role. But I still like the concept in game. This is what I do. I have software that lets me share a map and progressively reveal it as it is explored. Most VTTs offer this functionality and you can get the same effect for free with GIMP if you are willing to spend time learning how to do layers.
The players like being able to see the map as they explorer. But here's the thing. There must be a character with cartographer tools for me to show the map. If that character dies or is unconscious or doesn't join for the session, I don't reveal anything new. I'll just describe things and we play theater of the mind.
Because of this cartographer tools has become a very valuable skill. Parties will want multiple characters with this skill and may hire out a hireling cartographer because of the advantages of getting the map revealed and shown.
Note that cartographer tool use is basically treated like a passive skill. They are assumed to be focused on mapping, so they do not get to use passive perception or other passive skills. Other players have to take on the duty looking for traps and enemies, etc. If there are architectural or magical tricks I may make the cartographer make an active skill check. Though for exceptionally high illusion magic, etc., they may just fail their passive and keep going until they realize something is off. For this to work, I need to have correct and incorrect versions of the map, also it is annoying if done too often, so this is a rare trick.
Caller
That's because D&D was often played like a war game with war gamer conventions and often with large numbers of players. I refuse to run games for more than six players, and six is pushing it for me.
Initiative Tracker
I used to have a player track initiative, but now I use software for this, which is simpler.
Loot Tracker
It is up for the players to track their loot. Usually there is one player who records loot during the game and it is divvied up at the end of the session.
Note Taker
This is a task for each player. It is their responsibility to take notes. But I'm not a jerk about it. I'll let the player make an intelligence check to remember something from a prior session. I may make minor changes or give more or less detail depending on how well they roll. This still give a strong advantage to players who take notes without punishing players who hate note taking.
Co-DM
One thing I've done long ago and would like to do again is have a co-DM to run NPCs help with combat, etc. As an example of this, see the podcast Dragon Friends.
For milestone BBEG encounters, I'm thinking of bringing in a guest DM to run the BBEG as deadly as they can. Basically they would run the BBEG as if they are competing with the players. I would run minons and track effects etc. Often these settings have multiple BBEGs so it helps to have multiple DMs playing against the characters.
