Hint: Don't use Frozn for Deathmatch Extended. Very weak compared to all other clans. But, Frozn is very strong in Standard DM if you combine them correctly.
There's no tips on cards to use, all depends on playstyle.
Stongest clans in Standard:
•Rescue (If played correctly)
•Pussycat (but very slow and annoying)
•Skeelz (Not as strong now though)
All depends on playstyle. Best Leaders are:
•Hugo (For All Stars, Uppers, Sakrohm)
•Morphun (For Piranas and Vortex)
•Eyrik (For Sakrohm, Uppers, Junkz)
Hugo is not as good on Attack Manip. Clans as Eyrik and Eyrik is not as good on Power clans like Hugo. You'll understand if you ever play in-depth DM.
Bangers and Ulu Watu are also strong...
Heck, I can probably list all the clans in UR, BUT you must understand they all have weaknesses and strength, you need to know how to play them and understand their mechanics.