Reddit mentions of M-D Building Products 56032 1-Feet by 1-Feet Galvanized Steel Sheet

For metal minis there are typically two generally types of solutions.

1. You can get foam trays from a wide variety of companies, either pluck style or with pre-made compartments. This works well, I have four ArmyTransport trays that hold two factions worth of Infinity models. There are also nice bags made to hold the trays.
   
   
2. You can glue magnets on the underside of the base and stick them to metal sheets in some sort of container (or a metal toolbox). Sometimes this may require a little creativity to figure out the best way to "stack" multiple layers of metal sheets but fortunately Infinity doesn't use a lot of minis so one sheet may last forever.
   
   For instance, I'm magnetizing my Star Wars Legion models this way.
   
   I'm using this 13x13 container with has 4" tall "levels":
   https://www.amazon.com/Snapware-Seasonal-Ornament-Storage-Container/dp/B00FXLTSI6/ref=sr_1_1?ie=UTF8&qid=1522936303&sr=8-1&keywords=ornament+storage+13x13
   
   I'm using this 12x12 sheet:
   https://www.amazon.com/gp/product/B000W6ZMQY/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1
   
   The sheet drops right in, I've secured it with some double-sided tape or you can use glue or whatever. Then I put 6x2mm magnets on the bottom of each figure. You'd want to check the Infinity bases to make sure how thick a magnet will fit the recess but basically that's the process. Metal minis are heavier so you might want a slightly bigger magnet or perhaps two smaller ones. There are probably recommendations online somewhere.
   
   It's fairly cheap, very expandable, and should be able to hold nearly any game.

I used 1x1 foot galvanized steel sheets I cut to size to fit in the box with a pair of sheet cutters https://www.amazon.com/gp/product/B000W6ZMQY/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1