Just picked up some card holders for my underworlds games from 4GROUND publishing, pretty good at keeping tokens and upgrading cards organised during play.
(Picture taken from the website) I mainly play 3-4 character warbands such as the Wurmspat, Rippas Snarlfangs or Yltharis Guardians and these seem ideal for small warbands that stack up a few upgrades and damage during play. They seem a bit overkill for larger warbands who's characters don't get a lot of table time.
Not a bad idea though, I've found them quite useful when keeping track of +1/-1 wounds and such.
If anyone is interested, I picked them up from here https://www.4groundpublishing.co.uk/flux-construct