Here is the full list of all 58 Paladins achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Kill more than 20 enemy champions in a single match.
Reach a 20 kill streak in a match
Kill a player in the air who is over 100 units above the ground.
Win a match where the enemy team scored no points.
10 Double Kills.
50 Double Kills.
100 Double Kills
200 Double Kills.
400 Double Kills.
1 Champion at Mastery 5.
2 Champions at Mastery 5.
3 Champions at Mastery 5.
4 Champions at Mastery 5.
5 Champions at Mastery 5.
6 Champions at Mastery 5.
7 Champions at Mastery 5.
8 Champions at Mastery 5.
9 Champions at Mastery 5.
10 Champions at Mastery 5.
Survive more than 50 battles with less than 10% health.
Land 5 headshots in a row without missing.
Play 5 hours with a player from your friends list in your party.
Play 10 hours with a player from your friends list in your party.
Play 25 hours with a player from your friends list in your party.
Play 100 hours with a player from your friends list in your party.
Play 250 hours with a player from your friends list in your party.
Play a match while in a party.
Play 10 matches while in a party.
Play 20 matches while in a party.
Play 50 matches while in a party.
Play 100 matches while in a party.
Reach level 30 during the Paladins Beta.
Deal damage to every enemy champion in a match before any of them damage you.
Kill an enemy champion after they had already killed you.
Complete the Paladins Tutorial.
Kill an enemy player who is on a 15 killstreak or higher.
Get a killing blow after the round has ended.
Die to an environmental hazard.
Deal more than 100,000 damage during a match.
Be the only player alive in a match.
Unlock 100 Cards.
Kill an enemy player while you are at or below 50 Health.
Kill a player with an environmental hazard.
Kill an enemy player from over 300 units away.
Unlock Ranked
Shield over 200,000 damage in a match
Heal over 100,000 health in a match
Get a daily reward 7 days in a row
Build your own custom loadout
Play over 300 matches
Earn over 500,000 Gold over your play history
Earn over 1,000,000 Gold over your play history
Spend over 100,000 Credits in the item store over all your matches
Reach Master in Ranked
Have a Paladins account over 1 year old
Have over 30 different champions at mastery level 10 or higher
Have over 30 different champions at mastery level 15 or higher
Have over 30 different champions at mastery level 20 or higher