its looking good so far. golgari is one of my favorite guilds to build around. i would recommend adding
grimoire of the dead to help you load up your graveyard and later you can pull all your creatures plus your opponents for a quick finish. if you can get your hands on a few dredge cards they can really help,
shambling shell would be great in this deck and its not too expensive. heres my Gitrog deck if you want some ideas
https://deck.tk/8SbB92kr