I use La Junta and Uppers mainly for Survivor Elo. But I guess you can try out Pussycats and Freaks, especially when you reach more victories.
Personally, I would steer away from clans like Skeelz, Junkz, Piranha, etc. that generally has low damage and usually require 3 wins out of 4 rounds in order to win the match as you can't afford the pills later on. I would also not use the All Stars because I personally find that they are better at pilling high, which is something you can't do as your pills decrease.
Mono Uppers, Sakrohm or Skeelz would be what I'd use. Uppers have high attack manip and strong cards so they can hold their own even in a bad hand. Sakrohm have decent attack manip and game changing abilities that will help you, only problem is Soa and Skeelz are rediculously strong in mono, have a bit of everything, high power, high attack manip, big abilities etc.
Uranus (often banned however) and if he is banned use Corrina
All of those decks have worked for me and should be able to get you 10 + with a little bit of training and some luck.
Try looking through public presets to see what decks appear from your favorite clans
you can adjust settings to popular survivor elo decks for up to 2 clans
Jungo is, in my experience, generally the best clan in survivor elo.
You likely will need some form of dr once you get around survivor 5 or so. You will want to use a deck that you can hypothetically win one in three rounds and pull off the match. When you get above survivor ten, you have a large pill gap from the get-go, but also a decent life gap. You want a deck that can take advantage of that life gap with defensive cards.
Attack manipulation is good in every format, and survivor elo is no different. Attack manipulation can turn around a pill gap pretty quickly, and thus set you on equal footing with an opponent who is not as far along in the survivor numbers.
Sample deck that has done well in survivor elo multiple times: Jean, Pegh, Boohma, Troompah, Bubba, Rodney, Radek, Nyema (You can pick your favorite 3 stars, there are a lot of good ones in Jungo). This deck has a lot of attack manipulation, walls in the form of Buba and Radek, and some great life gapping potential (Nyema, Troompah, Buba, and Boohma all make a 7 point life gap w/o fury), additionally it has some dr and a soa card for defensive abilities. It does have a much harder time against soa than many other decks, but the fact of the matter is, GHEIST and Roots are hit harder by the pill gap in later survivor rounds, and thus are less popular in the survivor room.
Survivor elo is probably my favorite format in UR. I hope you enjoy it as well.
I got my best scores with Rescue (Back when I didn't know they were for n00bz) and recently a survivor 11 with Piranas.
Rescue's attack manip makes them good at olding, whereas Piranas pillz manip makes up for losing pillz later in the streak. Piranas are a bit more tricky to use, I'd suggest Rescue if you dont mind being ridiculed.
From experience, Jungo DOES work very well, but once you run into GHEIST / Roots might be gg (or poison as well)
also as a general rule, Piranas are SUPER scary towards those at like stage 5 because of their damage capabilities.
However, as a personal preference I usually try to look for one-round enders (such as poison, +life per damage cards) something like Oflgn is a great card for that purpose (but once again watch out for soa). my favorite would be either eddie or Karrion as they have great damage capabilities. eddie is good because he can win rounds easily with that 10 power. Karrion because he is less susceptible to soa and also has great teammates that would allow his own bluff (Cutey, Kenny Cr).