To unlock the Seal Savant trophy in Anthem, you will need to complete 12 of the Storm Gear challenges which can be found by opening the Menu > Challenges > Gear > Storm
You will find 13 challenges available -- one for completing four matches or open world events with a specific piece of gear equipped, and a final one for completing all 12 of the Storm challenges.
You pick up the gear as random mission rewards and from dead enemies. You can add two weapon gear and one support gear at once at the Forge. Once you have completed four missions with one set, head to the Forge and equip the next set to continue making progress towards the trophy.
Frost Shards I: Completed 4 Missions or World Events with this gear equipped
Lightning Strike I: Completed 4 Missions or World Events with this gear equipped
Wind Wall I: Completed 4 Missions or World Events with this gear equipped
Arc Burst I: Completed 4 Missions or World Events with this gear equipped
Burning Orb I: Completed 4 Missions or World Events with this gear equipped
Flame Burst I: Completed 4 Missions or World Events with this gear equipped
Glacial Spear I: Completed 4 Missions or World Events with this gear equipped
Ice Blast I: Completed 4 Missions or World Events with this gear equipped
Ice Storm I: Completed 4 Missions or World Events with this gear equipped
Living Flame I: Completed 4 Missions or World Events with this gear equipped
Quickening Field I: Completed 4 Missions or World Events with this gear equipped
Shock Burst I: Completed 4 Missions or World Events with this gear equipped
Storm Gear I Master: Completed all other 12 challenges