Let's see if SEs involve mentors dying!!
Firestar's Quest- N/A, Bluestar is already dead
Bluestar's Prophecy- Yes, Sunstar dies off screen :C
SkyClan's Destiny- N/A, Leafstar and Stick had no mentors
Crookedstar's Promise- No
Yellowfang's Secret- Sagewhisker dies of a heart attack
Tallstar's Revenge- Yes, off-screen :C
Bramblestar's Storm- N/A, Firestar is already dead
Moth Flight's Vision- N/A, mentors did not exist
Hawkwing's Journey- No, but Ebonyclaw does become a permanent kittypet
Tigerheart's Shadow- No, Oakfur is still alive to this day
Crowfeather's Trial- N/A, Mudclaw is already dead
Squirrelflight's Hope- N/A, Dustpelt is already dead
Graystripe's Vow- N/A, Lionheart is already dead
Leopardstar's Honour- Yes, Whitefang dies in a Sunningrocks battle
Onestar's Confession- Yes, Deadfoot dies offscreen
Riverstar's Home- No, Arc survives
I'll double down.
Hollyleafs Story: Nope, Brackenfur is alive.
Mistystars Omen: Echomist is already dead.
Cloudstars Journey: Idk, we don't know his mentor
Tigerclaws Fury: Nope, Thistleclaw is already dead.
Leafpools Wish: Nope, Cinderpelt is already dead.
Dovewings Silence: Nope, Lionblaze is alive.
Mapleshades Vengeance: Nope, Bloomheart lives.
Goosefeather's Curse: Yes, Cloudberry dies.
Ravenpaws Farewell: Nope, Tigerstar is dead.
Spottedleafs Heart: Nope, Thrushpelt and Featherwhisker survive.
Pinestars Choice: Yes, Mistpelt dies in a timeskip.
Thunderstars Echo: N/A, Never had a mentor.
Redtails Debt: Nope, Halftail lives.
Tawnypelts Clan: Nope, Brackenfur is still alive.
Shadowstars Life: N/A, she never had one.
Pebbleshines Kits: Nope, Billystorm was already dead.
Trees Roots: If you count his father, then yes.
Mothwings Secret: Yes, Mudfur dies in a timeskip.
Daisys Kin: N/A, she never had one.
Blackfoots Reckoning: Idk, we don't know who it is.
Spotfurs Rebellion: Nope, Leafshade is still alive.