Riot Games made good on its promise from 2019 about League of Legends' Prestige Edition skins by naming several champions that'll get Prestige skins in early 2020. The six champions Riot has named so far are Senna, Zyra, Zoe, Garen, Malphite, and Lucian. Some of those six champions were already known to be getting Prestige skins while others are ones that we're just now hearing about for the first time, and we still don't know what the themes will be for most of them.
Plans for the first half of 2020's Prestige skins were laid out in a post on the League site where Riot outlined the timeframes for these skins and how players will be able to obtain them. Senna's is the True Damage Senna skin that'll follow Qiyana's True Damage Prestige Edition cosmetic which was release late last year and will be obtainable with Prestige Points. Garen's is Mecha Kingdoms Garen, a skin that's part of the ongoing Mecha Kingdoms event.
Those are the only two that players already knew about though. The skins for Zyra and Zoe will be available for Prestige Points while the Malphite and Lucian skins will be available during events like Garen's. The champions were listed in the orders above in the two separate categories, so one would think that we'll see Zyra's and Malphite's skins before the other two, though Riot hasn't laid out a detailed schedule yet.
If you don't end up collecting enough event tokens to get one of the Prestige skins that's only available during events, you'll be able to purchase them at the end of the year with whatever Prestige Points you have left over.
For anyone who wants to start building up their Prestige Point banks to get the skins whenever they're released, you can go ahead and start earning those now. Riot said that the 2020 Prestige Points are now available from Masterwork Chest bundles, though you'll have to wait on Senna's skin to release if that's what you were planning on spending them on. Players have until February 3rd to use any Prestige Points they acquired from 2019, and for the points that you earn this year, you have until January 28, 2021, to use them.