These are all legit, event Pokemon. I will be posting links to validate their legitimacy. I'm asking for shinys I don't have; that's all. Some trades will require 2 for 1 because it is either shiny and/or battle ready.
Event Pokemon:
Keldeo (Japan 2012; 5IVs): http://www.serebii.net/events/dex/647.shtml
Hoopa (Japan 2015; 5IVs): http://www.serebii.net/events/dex/720.shtml
Meloetta (Japan 2012, 3IVs): http://www.serebii.net/events/dex/648.shtml
Victini (America 2012, 3IVs): http://www.serebii.net/events/dex/494.shtml RESERVED
Rayquaza (Japan 2012, 4IVs): http://www.serebii.net/events/dex/384.shtml
Mewtwo (America 2012, 5IVs): http://www.serebii.net/events/dex/150.shtml
Pikachu (America 2015, 4IVs): http://www.serebii.net/events/dex/025.shtml
Giratina (America 2013, 5IVs, shiny): http://www.serebii.net/events/dex/487.shtml
Entei (America 2011, 4IVs, shiny) http://www.serebii.net/events/dex/244.shtml
Suicune (America 2011, 3IVs, shiny) http://www.serebii.net/events/dex/245.shtml
Raikou (America 2011, 4IVs, shiny) http://www.serebii.net/events/dex/243.shtml
Scizor (Japan 2012, 4IVs) http://www.serebii.net/events/dex/212.shtml
Pokeball Pattern Vivillon (America 2014, 4IVs) http://www.serebii.net/events/dex/666.shtml
Fancy Pattern Vivillon (America 2014, 4IVs) http://www.serebii.net/events/dex/666.shtml
Hydreigon (Japan 2011, 4IVs, shiny) http://www.serebii.net/events/dex/635.shtml
Diancie (America 2014, 5IVs) http://www.serebii.net/events/dex/719.shtml
Halloween Gengar (America 2014, 5IVs, shiny) http://www.serebii.net/events/dex/094.shtml
Halloween Pumpkaboo (America, 4IVs) http://www.serebii.net/events/dex/710.shtml
Arash Ommati's VGC Nationals Mamoswine (America 2014, 5IVs, shiny) http://www.serebii.net/events/dex/473.shtml
Pokémon World Championships 2014 Aegislash (America 2014, 4IVs) http://www.serebii.net/events/dex/681.shtml
Pokémon National Championships 2015 - Sejun Park's Pachirisu (America 2015, 5IVs) http://www.serebii.net/events/dex/417.shtml
Note: RED font Pokemon cost 2 shinys.
I will be adding more Event Pokemon in the future to update this list if I see I get a lot of trades.
Event Pokemon:
Hoopa (Japan 2015; 5IVs): http://www.serebii.net/events/dex/720.shtml
Victini (America 2012, 3IVs): http://www.serebii.net/events/dex/494.shtml RESERVED
Rayquaza (Japan 2012, 4IVs): http://www.serebii.net/events/dex/384.shtml
Mewtwo (America 2012, 5IVs): http://www.serebii.net/events/dex/150.shtml
Giratina (America 2013, 5IVs, shiny): http://www.serebii.net/events/dex/487.shtml
Entei (America 2011, 4IVs, shiny) http://www.serebii.net/events/dex/244.shtml
Suicune (America 2011, 3IVs, shiny) http://www.serebii.net/events/dex/245.shtml
Raikou (America 2011, 4IVs, shiny) http://www.serebii.net/events/dex/243.shtml
Scizor (Japan 2012, 4IVs) http://www.serebii.net/events/dex/212.shtml
Pokeball Pattern Vivillon (America 2014, 4IVs) http://www.serebii.net/events/dex/666.shtml
Fancy Pattern Vivillon (America 2014, 4IVs) http://www.serebii.net/events/dex/666.shtml
Hydreigon (Japan 2011, 4IVs, shiny) http://www.serebii.net/events/dex/635.shtml
Diancie (America 2014, 5IVs) http://www.serebii.net/events/dex/719.shtml
Halloween Gengar (America 2014, 5IVs, shiny) http://www.serebii.net/events/dex/094.shtml
Halloween Pumpkaboo (America, 4IVs) http://www.serebii.net/events/dex/710.shtml
Arash Ommati's VGC Nationals Mamoswine (America 2014, 5IVs, shiny) http://www.serebii.net/events/dex/473.shtml
Pokémon World Championships 2014 Aegislash (America 2014, 4IVs) http://www.serebii.net/events/dex/681.shtml
Pokémon National Championships 2015 - Sejun Park's Pachirisu (America 2015, 5IVs) http://www.serebii.net/events/dex/417.shtml
Note: RED font Pokemon cost 2 shinys.
I will be adding more Event Pokemon in the future to update this list if I see I get a lot of trades.