Considering I've started to play this game a lot more recently compared to last year and the year before (when people were saying TF2 is dying and I was playing games such as CSGO to follow the hype train), I'm just going to suggest things that I found really enjoyable back in 2012-2013 time when I played TF2 a lot in an attempt that others here will agree that they enjoy.
VSH / Freak Fortress - This is pretty much a given. I'm sure at least 95% of the people here have played it and at some point enjoyed it. A good variety of maps is always key and it's a fun game mode whether you have 6 players or 24.
Balloon race - When one of my favourite Freak Fortress servers shut down, it changed to a balloon race server a week later. I was a bit on edge about this, but it's still really fun either way and I had a great time playing it. It mixes the fun modded side of TF2 with the vanilla aspect of Payload Race, so I found it a fun alternative to standard game modes.
Deathrun - Probably my favourite game mode. I used to play this for hours on end. I'd come home from school and play this for a solid 6+ hours straight. With a good mix of maps and high player count, it's by far really fun and one of the best game modes I'll ever play.
Standard game modes (with custom maps) - I'll say it, but the old TF2R server had these and I found them to be really fun. For example, there was this one control points map that was set on a moving train (I can't remember the name of it, if someone knows what it is please respond) that will always be stuck in my mind because it was so damn fun. But yeah, just an idea.
Other potential game modes, these are ones that I haven't played much of, but are still out there for suggestion:
x10 server - The idea of having stats multiplied by 10 would certainly cause mayhem for certain weapons, could be a fun spin-off for regular maps.
Randomizer - Having loadouts randomized could also be a fun spin-off for regular maps.
MvM - I've always enjoyed MvM, but the only problem is that the user count is very limited with 10 usually being the highest amount of players that can play at any one time. This could be good as an extra server, but it might not be worth it.
In regards to promotion of servers and such, I am always willing to raffle daily both inside and outside of chat as I love raffling for the community. I enjoy playing on the ScrapTF server with other fellow people from the community and in regards to moderation of the servers, I'm also more than willing to do so (even though I'm inexperienced), but either way I'll still enjoy sitting on the ScrapTF server(s) and playing / talking with others.