I've been playing TSG for the last month or so; it's my current pet deck. My list is straight reanimator.
There's a certain package of graveyard-based cards that TSG just demands. Search for Azcanta, JVP, Looter il-Kor, Careful Study, Chart a Course, Frantic Search, Champion of Wits, Fact or Fiction are all so good both with him and just as card advantage that I can't imagine any TSG deck not running them. Hedron Crab is an all-star too, and some of the Dredge cards can help. Once you've got those cards you want Torrential, you want Snapcaster if you can afford it, and you want Dig Through Time and Treasure Cruise, which then ask you to run a few more cantrips/tutors to power them. Even cheap cycling cards like Striped Riverwinder and Street Wraith start looking pretty good, though I haven't found room for them yet.
Now you're set up to pretty consistently find cards you want, while filtering cards into your graveyard. You're going to want to be putting creatures into your graveyard for TSG anyway, so you probably also want Buried Alive, Entomb, Reanimate, and some quality creatures to eternalize, preferably ones that don't depend on their size - Jin-Gitaxias, Rune-Scarred Demon, Consecrated Sphinx are all prime targets, while Tidespout Tyrant loves all the cantrips and Grave Titan makes TSG go off immediately. But now that you're so good at putting creatures in you're graveyard, you don't really want to have to wait until 9 mana to cast TSG + activate him, so there's Living Death to win you the game on the spot, and targeted reanimators like Reanimate, Exhume, and Stitch Together, plus the enchantments (Animate Dead, Dance of the Dead, Necromancy). The enchantments make you want Kederekt Leviathan (it'll bounce all other permanents including the enchantment and then die, giving you a boardwipe every turn if you want). There's some tension between Kederekt and Living Death, but that's not a huge issue; if you think you're on LD and Kederekt is in your graveyard, either reanimate it first or delve it away.
Pretty much everything else in my list is ramp or interaction. It's only running 33 lands (my paper build might have gone down to 32, I forget) so it has to be able to operate if it starts missing land drops early; rocks and rituals are essential. This also means I prioritized cheap interaction, so my counterspells don't generally hit creatures, so a decent removal suite is necessary (also, killing TSG is a nice in a pinch to save him from more permanent removal). Murderous Cut is another solid Delve spell. Cyc rift and Cryptic are crucial for dealing with noncreature permanents.
Finally, I think with EDH reanimator in general you'll find that 6cmc is really the sweet spot, where creatures are pushed enough that reanimating them early will win you the game, but still cheap enough that you can cast them if the reanimation plan fails. I currently have 10 creatures I'd call "targets", of which 6 are at 6cmc, making only 4 cards in the deck that are really difficult to cast. You always want to avoid dead cards where possible.