While we can filter the Squad or Tactics screens (or most screens in the game, for that matter) by players in certain positions etc. i think it would be useful to have a 'custom selection' option.
For example: I am trying to compare the performance of my full backs (see attached screenshot). However, I only want to see the players who I intend to use as a full backs - the screen is a little messy showing far more information than I need, as I'm not interested in seeing JD Costello, Jassem Sukar or Ben Hedley in my filtered list .
Thankfully my squad is extremely small; it would be even more difficult to visually pick out the information I want to see from a bigger list of players (or trying to compare your top 5 transfer targets from a shortlist of 30, for example)
I feel like it would be pretty easy to implement, just a simple checkbox called 'Custom Selection' or something along those lines, and once that is ticked you have checkboxes next to each player with a 'Confirm' or 'Apply' button to set that filter?