So I wanted to build sand with Mega Chomp since that's been picking up usage as of late. I also knew that I wanted to build a more Balanced approach since all the other teams here are pretty much BO and I hadn't built Balance in awhile, so I wanted to give it a try here. Thus, Hippowdon was the obvious second choice and along with Mega Chomp stars as the core of the team. While it wouldn't be entirely impossible to build Sand Balance using TTar, I felt that I'd be more constrained in my options moving forward so that's that. Ferrothorn + Toxapex are the next 2 members, and they synergize generally well with the team and with each other, so not much to comment on there. I struggled for a bit to find an ideal last two, and I think the ones I have rn are generally the best last 2 picks for my team and compliment the team pretty well. I picked Torn-T for the next slot since it compressed a lot of much needed roles into one slot. It gave me a defogger, a check to threatening Grass-types and Fighting-types, and it gave me another out vs stall with Taunt + Knock Off being very annoying to face. Torn-T also pairs well with Toxapex since they form a Regen core together which helps vs stall and very fat Balance teams. Lastly, I picked Jirachi for my "Flying" resist, and while of course it's not the best thing in the world for a Flying resist, it suffices well enough for what I needed. It's good speed control and can pivot Mega Chomp into a favorable position to wallbreak. The icing on the cake with Jirachi was its access to Healing Wish, which let's the team play a little more aggressively for a Balance team with Healing Wish in the back. As a bonus, Jirachi is a nice revenge killer for most Psychic-types, which can especially be problematic if Ferrothorn goes down early or it gets too worn down to the point of not being able to properly check them. I don't want this to be too much longer since it's plenty long, so if you have any concerns / questions about certain moveset choices or EVs, feel free to ask me about them, since they all have a purpose.
EDIT: Whoops I just realized that the Hippo spread I actually calc'd with Leftovers, it was supposed to be able to take 3 HP Ices from Zapdos after rocks so you weren't as pressured to click Slack Off vs it the first turn it came in and you could throw off a Toxic but looks like I messed up on that. Fixed since I don't see much of any other reason to invest into SpDef, but if you opt for Leftovers on Hippo instead of Rocky Helmet since it is a valid choice, I'd go for the original 252 HP / 184 Def / 72 SpD spread that I posted. My bad lol