Out of all fossil Pokémon (excluding the ones from X and Y, as they're a little early to judge due to being new), my favorite would have to be Bastiodon. Its head looks like a gigantic shield, which is quite awesome! Thanks to its head, this Pokémon's able to take in a lot of hits without being damaged too much. Not only that, Bastiodon's got a variety of moves in its arsenal as well, most of which you may find to be helpful when battling competitively. Some of these moves are Stealth Rock, Roar, Toxic, and Magic Coat. Stealth Rock gives you the chance to hurt your opponent's Pokémon as soon as they get sent out on the field, making it a bit easier for you to have them taken out. With Roar, you're able to force your opponent to switch their Pokémon if they're a threat to Bastiodon. Toxic allows you to cripple your opponent's walls, as well as some sweepers. And with Magic Coat, you can throw back any non-damaging move that your opponent uses on you. If you have all four of these attacks on your Bastiodon as a complete moveset, then your opponent should be having quite a hard time stopping you. (:
Armaldo is also one of my favorite fossil Pokémon. Its design is pretty nice, and I find its smile to be really adorable! The only thing that I don't like about it is its arms—in my opinion, they're kiiiind of placed in an awkward position. If the arms were a little higher on its body, then it definitely would have looked better. From a competitive standpoint, Armaldo isn't that bad either. Its base Attack stat is one twenty-five, which is very decent. After the use of Swords Dance, this Pokémon could sweep just about anybody!