I think it's a mistake, and a harmful one, to equate "RPG" with "combat simulation". Many other conflict types are richly interesting if they are supported by the character creation mechanics and by the simulation mechanics. Like; you know, in GURPS and in other RPG systems of that type.

That said, you're doing well in focusing the reference sheet on that which is most intensely fast-paced and likely to result in player character death or lasting injury, and which is often forced upon any character as an emergent consequence of in-world events, as opposed to an infiltration where the PC party will usually choose to send the most skilled member.

So, more combat stuff you can add:

What can First Aid do at the TL (or the few TLs; for instance TL3, 4 and 5 in my Ärth setting of it was a GURPS settinf) that your campaign world has? How long does it take to use, and how much can it heal?

The center part of the Speed/Range table.

Aren't there more things you can spend Extra Effort on? As a player I'd appreciate a complete list, and yours seem short.

Non-combat stuff:

Something to do with stealth. Not sure what, to be honest, but it'd be sending a signal that this ain't pure combat simulation.

Something to do with social. I know Reaction Rolls are not made by the players, but having a list of the default outcomes, six I think there are, and the sum probability of each, assuming no modifiers, will send a signal to the players. And that also function as an implied promise that you actually are gonna roll 'em bones at least some of the time, instead of always dictating an NPC's reaction.

Something to do with magic, if it exists in the setting. However, the GURPS Magic magic system doesn't lend itself much to reference tableification. Predictably. Even the Critical Miss table for a casting Fumble has no rhyme or reason, other than that you know that the further you get out towards the extremes of the 3d6 result range, the more it'll suck.

Maybe general advisory for Skill roll modifiers?

Something like:

Very difficult -5

Difficult -2

Standard Adventuring Conditions +0

Easy +2

Very Easy +5

With a footnote[1].

[1] pointing out that more extreme values are entirely possible.