The shop opens on December 9, 2021 and will be open until March 24, 2022 when the Mythic Content Overhaul begins.
Tl;dr 
Event Prestige Skins are skins that were previously available in Event Shops only and do NOT include their original event exclusive icons and borders. Each of these will be available for 100 Prestige Points (2020).
- Mecha Kingdoms Garen Prestige Edition
- Dark Star Malphite Prestige Edition
- Pulsefire Lucian Prestige Edition
- Spirit Blossom Teemo Prestige Edition
- PsyOps Ezreal Prestige Edition
- Obsidian Dragon Sett Prestige Edition
- K/DA ALL OUT Kai’Sa Prestige Edition
- Battle Queen Diana Prestige Edition
- Lunar Beast Fiora Prestige Edition
- Space Groove Lulu Prestige Edition
- PROJECT: Sylas Prestige Edition
- Ascended Pantheon Prestige Edition
- Coven Leblanc Prestige Edition
- Nightbringer Kayn Prestige Edition
- Duality Dragon Volibear Prestige Edition
The following Prestige Point skins debuted earlier in 2020 and 2021, so they will already be in the Last Chance shop by default. These are also 100 Prestige Points (2020) each and include their matching icons & borders.
- True Damage Senna Prestige Edition
- Coven Zyra Prestige Edition
- Arcanist Zoe Prestige Edition
- True Damage Yasuo Prestige Edition
- Star Guardian Soraka Prestige Edition
- Battle Academia Leona Prestige Edition
- Conqueror Jax Prestige Edition
- PROJECT: Zed Prestige Edition
- Bewitching Morgana Prestige Edition
These icons were associated with Prestige Point bundles in past event shops. Each one is 5 Prestige Points (2020).
- Night & Dawn Event Prestige Points Icon (2019)
- Mecha Kingdoms 2020 Event Prestige Points Icon
- Galaxies 2020 Event Prestige Points Icon (aka Dark Star)
- Pulsefire 2020 Event Prestige Points Icon
- Spirit Blossom 2020 Event Prestige Points Icon
- PsyOps Prestige Point Icon
- Worlds 2020 Event Prestige Points Icon
- Battle Queens Prestige Points Icon
- Lunar Beast Prestige Points Icon
- Space Groove Prestige Points Icon
- PROJECT: Prestige Points Icon (2021)
- 2021 Coven Prestige Points Icon
- Worlds 2021 Prestige Points Icon