Here is the full list of all 36 Wild Frontera achievements.
Collect 4,751 gold
Spare the life of 100 bandits
Save 100 damsels
Complete all Stages in MOST WANTED difficulty
Buy all the character upgrades
Kill the Executioner with a punch as final blow
Kill the Bufferatops ghost first
Buy a Custom Quality Revolver
Destroy all the portals in less than 5 seconds
Kill the sow while 5 piglets are alive
Buy a Custom Quality shotgun
Kill the BergMeister with explosives only
Stand on the last platform at the end of the encounter
Buy a Custom Quality rifle
Reach a 5 star wanted level in co-op freeroam. "Now that's hard", Bestio.
Complete a stage wihtout dying
Kill Poncho Bob with 3 turrets up
Kill all the Banditos running from Poncho Bob
Find all the cards
Kill 1000 enemies
Complete all Stages in normal or easy difficulty
Complete Stage VIII in any difficulty
Complete Stage VII in any difficulty
Complete Stage VI in any difficulty
Complete Stage V in any difficulty
Activate all the detonators in less than two minutes
Complete Stage IV in any difficulty
Kill 8 minions in less than 20 sec while fighting the mysterious masked man
Complete Stage III in any difficulty
Do not let more than one sniper alive at the same time
Kill Bufferatops in less than 1min 30 sec
Complete Stage II in any difficulty
Do not let a single suicidal bandit explode while fighting SteelNugget
Complete Stage I in any difficulty
kill all the pigs before they flee near Pueblo del Norte
Resurrect a friend in a co-op game