27 cards where the card is tagged “lose-half-life”

Blood Tribute (Commander 2017 #100)
Chainer's Torment (Dominaria #82)
Cruel Bargain (Vintage Masters #111)
Death Wish (Judgment #64)
Dire Fleet Ravager (Outlaws of Thunder Junction Commander #132)
Doomsday (Masters 25 #88)
Ebonblade Reaper (Onslaught #141)
Fraying Omnipotence (Core Set 2019 #97)
Garza's Assassin (Coldsnap #57)
Goblin Game (Planeshift #61)
Havoc Festival (Return to Ravnica #166)
Infernal Contract (Seventh Edition #143)
Lurking Evil (Vintage Masters #127)
Murderous Betrayal (Eighth Edition #147)
Peer into the Abyss (Core Set 2021 #117)
Personal Incarnation (Masters Edition IV #22)
Pox (Masters Edition #82)
Quietus Spike (New Capenna Commander #377)
Raving Dead (Commander 2014 #29)
Revival // Revenge (Ravnica Remastered #241)
Rush of Dread (Outlaws of Thunder Junction #104)
Scourge of the Skyclaves (Zendikar Rising #122)
Scytheclaw (Commander Masters #408)
Shahrazad (Arabian Nights #10)
Skull Storm (Commander 2018 #18)
Temporal Extortion (Planar Chaos #81)
Virtus the Veiled (Battlebond #7)

Though this query has ended, its relics still slumber in New Argive.