A while ago league player XDemonic25 made a program which replaces the default announcer with custom ones and allows players to make their own. Riot has allowed this program to exist and
Pyke Announcer - KillerSkins
How to Use Custom Announcer Packs for League of Legends?
Overwolf - Set the soundtrack to your gaming and rock some custom announcer packs when you're playing LoL, Rocket League, Fortnite, or CS:GO with the Apollo app. Available on Overwolf: https://www.overwolf.com/app/Players_Republik-Apollo
How to Use Custom Announcer Packs for League of Legends?
Custom clone announcers at Star Wars: Battlefront II (2017) Nexus - Mods and community
Announcer pack: Rick and morty - KillerSkins
カスタム音声でLoLを楽しむ - C9 Announcer Pack | orz.game
Gangplank Announcer - KillerSkins
Announcers - KillerSkins
How to make a Custom Announcer for League of Legends - YouTube
Riot teases League of Legends announcer packs coming soon - Dexerto
A Netherim custom announcer for League of Legends : r/leagueoflegends
Star Guardian Ahri Announcer
How to make a Custom Announcer for League of Legends - YouTube
How to turn off the custom MSI announcers - The Rift Herald
Jhin: The Virtuous Announcer (Custom announcer for League of Legends) - YouTube
How to Use Custom Announcer Packs for League of Legends?
Gawr Gura announcer pack for LoL (Test) : r/Hololive
How To Easily Install Custom Voice Pack in League of Legends
THE DRUTUTT CUSTOM ANNOUNCER IS HERE! (Full showcase) - YouTube
How To Easily Install Custom Voice Pack in League of Legends
Announcers - KillerSkins
Custom Announcer Tutorial for League of Legends (Season 12) - YouTube