(I'm only counting the ones that actually happened and the tourney actually completed)
osu! Malaysia Tournament 2015: Quarter Finals (my worst performance ever)

Z-Tourney: Group stages
Team Bolehians: Jeffrey, zisamEr, Ex6TenZ, L u m i n o u s, TayGames, BornBorn, [R-M-T] Yozora

Sexual Tentacle Monthly Tournament Feb 2016: Quarter-finals
Team OK DAD: Jeffrey, Ex6TenZ, Moen-, L u m i n o u s, Raen, Lumision, ffstar

osu! Southeast Asia Tournament: Ro16

OTT: Quarter-finals
Team seamen: phox, Ex6TenZ, Jeffrey

Project Winter Tournament: Quarter-Finals (Loser's bracket round 4)

Manteifa Creative Tournament: Ro32
Team maybe: kuur0, phox, Rumia-, Reset-, Jeffrey

Hippo Cup: Quarter-finals
Team seamen: Lunarsol, Fuma, Jeffrey, [ Sakura_Ame ], Rexeez, -okaysonz-, ShaneLiang, wailord2700

Arcanus New Year Blast: Ro16
Team TemporaryV3: Jeffrey, kuur0, Reset-, Yellowraven, Cyndere, Vexine

Sexual Tentacle Monthly Tournament Winter 2018: Group stages
Team life is good: kuur0, Yellowraven, Vexine, Fuma, Rampax, Jeffrey, wuhua, Tzero

osu! TV-Size Tournament: Quarter-finals
Team ANGERY JEFFREY: Jolene, Jeffrey, haruchi, moosepi, LanJay, Rampax, Desumond

osu! Multi-Mode Contest #2: 22nd place
Team Petani Malaysia: Bedwyr Aorta, Minisora, walaowey, Jeffrey

Test Tournament: Quarter Finals
Team Seamen: ALtist, phox, Ex6TenZ, King Hong, Jeffrey, Fuma, dika312, sinn, DaNoobSlayaar, Desumond, Rampax, ZheVulture, LoidKun, Mak Kau Hijau, ShaneLiang, Vexine

Gotta Aim Fast Tournament: Group stages
Jeffrey's pp compilation: Landegre-, Fuma, Jeffrey, Skydiver, ShaneLiang, _Kumiko-chan_, [ Sakura_Ame ], Rexeez

Team Duel: Quarter Finals
Team Besties: Skydiver, Sora Yuuki, [ Mystic ], conradmittn, Fuma, Jeffrey, Kurosaki, ShaneLiang

osu! Malaysia Tournament 2018: Top 12

Southeast Asia Royal Rumble Tournament: Quarter-finals

Neko Meow Meow Cup: 7th/8th place (seriously fuck this tourney lol i rate it 2/10 quite terrible damn lanjiao)
女神露米亚: Jeffrey, King Hong, Rumia-, ALtist, Desumond, wuhua

Champs de Carbone: Ro16

Qualified to join the Malaysian OWC team (but sadly didn't qualify for OWC)

osu! Southeast Asia Tournament 2: top 24

Bean Tourney: Ro32 (Lost to mook and fuffarin)
Where Love Lies: Fuma, Jeffrey

Spork Cup: Ro32
doko?: TequilaWolf, Tzero, Jeffrey

Enigmatic Snow Festival: Top 8 (?)
fine with anything: Fuma, Tzero, Jeffrey, k_1tty, woahsia, Raindrop, sinn, dika312

Pls Enjoy Tournament: Quarter finals
KMS Squad: woahsia, k_1tty, Jeffrey, Zygody

4-digit World Cup: Ro16
Malaysia: Jeffrey, ClawViper, ffstar, King Hong, Zygody, not_aweeb

osu! Stay-In Tournament: #9

Icicle Heat Tournament: Quarter Finals
Malaysia: Zygody, Jeffrey, Chiyuu, Reinaru, not_aweeb, vernonlim

osu! Malaysia Tournament 2020: 7th - 8th

osu! Battle Archive Malaysia: Quarter finals
Monkeybsns: ClawViper, Jeffrey

Staff positions:
OMT 2015: Commentator, referee
OMST 2016: Host, commentator, referee
o!SEAT 2017: Commentator, referee
OTST 2018: Commentator
TEST 2018: Pool tester, commentator, referee
SEARRT: Commentator, referee
OMT 2018: Commentator, referee
o!SEAT 2: Commentator, Streamer
o!MAT: Co-host, Pool selector, Streamer, Referee, Commentator
OTST 2019: Commentator, Referee
OMT 2019: Pooler, Streamer, Referee, Commentator
SEARRT 2: Streamer, Commentator
OIT 2020: Mappool tester
o!SIT: Streamer, Commentator
OMT 2020: Commentator
SSSS: Referee

Jeffrey Is Bald As FK! Is That His Secret To Play Better? U Think The Loss Of Hair Allows WJeffrey98 To Be Able To Be Consistent? My Prediction Is That The No Hair Allows Jeffrey To Be Able To Concentrate And To Move More Swiftly And Controllinglyed... I Bet His Head Feels Lighter Than The Rest Of The Squad... What Do U Guys Think? Do You Think Being Bald Is Allowed In The Game Similar To Touchscreen? Comment Ur Opinions Down Below!