Feature summary:

• Highlight globally/locally (b)locked users on Suggested Investigations
  • Special:Checkuser marks (b)locked accounts as (Locked) / (Blocked)
  • Opening all of the accounts listed in one investigation via Special:MassGlobalBlock / Special:MultiLock (similar to how that's possible on Special:Checkuser) would also be helpful as both special pages indicate which accounts are already globally (b)locked. Unfortunately there's no way to directly open these special pages via SI – it currently involves a lot of copying and pasting.
  • Popular user scripts like m:User:Dragoniez/MarkBLockedGlobal or gadgets like en:MediaWiki:Gadget-markblocked.js cover the desired feature by striking through user names, but that doesn't work on loginwiki (where javascript is disabled) – and even on other wikis such scripts aren't a perfect solution as they tend to struggle with long lists of users
  • T398286: UserInfoCard: Use new icon to indicate sitewide blocked, globally blocked, or locked user might be helpful, but it would need be applied to global (b)locks as well. And It's not clear to me whether it would be sufficient to easily spot accounts which aren't (b)locked in long lists of users
  • Allowing CU / stewards to sort accounts within one SI report by (b)lock status might also be an option
  • T414979: Close the cases when all accounts are already blocked is helpful in making sure we're not wasting our time with long lists of users where all accounts are blocked already – similarly T418293: Suggested Investigations: Create a filter to filter out cases with no users blocked ensures the opposite which is also helpful

Use cases:

• Investigate a long list of accounts on Suggested Investigations, e.g. https://login.wikimedia.org/wiki/Special:SuggestedInvestigations/detail/66cd34f8
• Notice that many accounts are (b)locked already
• Attempt to (b)lock all of the other ones
• Spend a lot of time (or frustratedly quit) because you currently need to look at each account individually (e.g. by opening the UserInfoCard or Special:CA for each account one-by-one)

Benefits:

• Make it easier and less time-consuming to (b)lock all remaining sockpuppets – especially in long lists of users where it's hard spot which ones aren't (b)locked yet.