Quickest F2P way to get ISO??

I rank 2ed a bunch of 6*s and quickly ran out of iso levelling them up. Whats the fastest way to get iso besides just buying cavs?

Comments

GoDlyZor

grinding arena. I too have low iso but between shards from ranked rewards and occasional 4 and 5* from gmc I stay afloat. Some iso up for grabs this month in special objectives too

IAMGROOOT

I like to do the progression lvl objectives, those crystals can give you good iso. Alliance crystals as well

Lvernon15

grinding arena. I too have low iso but between shards from ranked rewards and occasional 4 and 5* from gmc I stay afloat. Some iso up for grabs this month in special objectives too

The_beast123

The arena this month gives the 3k ISO for every milestone, and it's not that tough either to grind it.
Incursions could help with the artifacts, and hence crystals to dupe, or just shards from milestones.
4 star crystals seem like the best way. GMC's rarely give 4 stars, so you could give a shot at them too. Same about PHC's and 3-star crystals, if you hoard them.
Uncollected objective crystal has come clutch for me quite a lot of times.

Quite a unpractical method, but the 4.3.6 Venom quest, straight to the boss, I think you get the 1.3K ISO there. Not much but still, yeah.
Doing the EQ also gives shards for 4 star crystals and etc (UC difficulty)
This months Side Quest is a 0 energy quest, so it's defintely your worth trying for the shards at all difficulties.