Here are your sources of i95+ weapons:

i95:
Leviathan Ex (req. Garuda/Titan/Ifrit Ex until 2.3)
Twintania (T5 Coil)

i100:
Leviathan Ex Mirror of the Whorl (super rare drop)
Relic Animus (Atma grind + 13500 myth Trial of the Braves book+fate grind)
PVP (Rank 40)
2nd Coil T7+T9 (Unidentified Tomestone + 1300 Soldiery)

i110:
Relic Novus (Alexandrite grind, more sources via Bounties in 2.3)
2nd Coil T8+T9 Sands of Time (upgrading i100 Weathered weapon, also as Crystal Tower drop in 2.3 but still need Unidentifed Tomestone somehow)


i115:
2nd Coil T9