Thanks +Robert Adducci
, although I couldn't find any guidelines mentioning what logos can or cannot be used, actually I thought I could use the D&D and DMsG logos, because of the legal line they recommend:
"We recommend a legal line in this general format:
DUNGEONS & DRAGONS, D&D, Wizards of the Coast, Forgotten Realms, the dragon ampersand, and all other Wizards of the Coast product names, and their respective logos are trademarks of Wizards of the Coast in the USA and other countries.
This work contains material that is copyright Wizards of the Coast and/or other authors. Such material is used with permission under the Community Content Agreement for Dungeon Masters Guild.
All other original material in this work is copyright  by [your legal name or company name] and published under the Community Content Agreement for Dungeon Masters Guild."
I thought (as the legal line even mentions "and their respective logos"), that it was clear they own it and all. So, this is really not clear (IMHO).
Also, the Community Content Agreement states, at 4a:
4. Rights Granted to You.
(a) Subject to your compliance with the terms of this Agreement, OBS grants you the limited, nonexclusive, nontransferable, personal, worldwide and revocable right to use and otherwise incorporate Owner’s IP and Program IP into your Work(s) for distribution through the Program or other platforms and channels at the sole discretion of Owner.
And by Owner's IP the same agreement states:
Owner’s IP includes any and all Dungeons & Dragons tabletop roleplaying materials and content made available to you through the Program including, but not limited to:
Dungeons & Dragons rule sets
Portions and elements of Dungeons & Dragons campaign settings
Artwork and other graphic templates and materials.
So, what does "not limited to" stands for?
As I said, it's really not clear, I would like they just clearly state, "here you can use this logo, but not these logos". How hard is that?
Again, thanks a lot for your tip, now I would love to find a way to be sure about this though.