Changes in the gameplay and types of Pokemon will not list, in each part hurts a lot of such changes. You find it easier to find on Bulbapedia.
Gen1:In 1996, Pokemon red & green for Nintendo GameBoy was released in Japan, for the Western market the games were converted into improved versions of Pokemon Red & Blue and released in 1998. After the HYIP wave related to the success of the anime, a special version of Pokemon Yellow (for GameBoyColor) was released, in which it was impossible to choose a starting pokemon, instead the only starting pokemon was Pikachu.
Kanto Region. 151 pokemon.
Gen2:Pokemon Gold & Silver 1999 was released in Japan, 2000 in the west, and also in 2001 an "improved" version of Crystal was released. For GameBoyColor.
Giotto region, 100 new pokemon, only 251 pokemon, but after the completion of the main campaign opens Kanto region. The main innovation was the use of inside game time for a cycle of day and night, where individual Pokemon could meet the player only during the day or night.
Gen3:Pokemon Ruby / Sapphire 2002 was released in Japan, 2003 in the west and 2004 was the release of the "improved" version - Emerald. For GameBoyAdvance.
The Hotnn region, added 135 new PokГ © mon, bringing the total number of available PokГ © mon up to 386. The battle of 2in2 was a significant innovation.
From this generation onwards (including remakes)
Not all pokemons out of a total of 386 can be caught on the map , to get some you have to go for tricks like transferring Pokemon from past games or participating in events.
Gen4:Pokemon Pearl & Diamond came out in 2006 in Japan, in 2007 in the west and in 2008 came the "improved" Platinum. For NintendoDS.
Sinnoh Region, 107 new Pokémon (total 493). The time of day change introduced in Gen2 was synchronized with the clock set on NintendoDS, and the possibility of online battles was also implemented.
Gen5:Pokemon Black & White came out in Japan in 2010 and in the west in 2011 for the Nintendo DS.
The Unova region, which added 156 new Pokémon, has a total of 649 available. Seasons of the year have been added to the game, changing every month.
Pokemon Black2 & White2 came out in one year for all regions, but the Japanese version came out 4 months earlier. This is a direct storyline continuation of B & W, in the same region, with the same Pokemon, with the addition of new locations and characters.
Gen6:Pokemon X & Y was released in 2013 simultaneously all over the world on the Nintendo 3DS.
Kalos Region, 72 new Pokémon added (total 721). Most of the game is translated into 3D. For some Pokemon, Mega-Evolutions are available, which can only occur during battles and disappear after they end.
Gen7:Pokemon Sun & Moon was released in 2016 for the Nintendo 3DS.
Alola region, which added 81 new pokemon (total 802).
Pokemon UltraSun & UltraMoon - improved versions with alternative storylines (but not a continuation of the plot, as it was in B2W2), came out in 2017.
In USUM, 5 more Pokemons have been added (total number 807), new content has been added for the game after the end of the plot.
In the Alola region there are also alola-species (differing in appearance) of Pokémon from the first generation.
Gen8:Pokemon Sword & Shield out November 15, 2019.
Region Galar, based on the British Isles. Returned regional varieties (Galar-specific evolution), the first game of the main series, in which all the Pokémon from the previous parts of the game will not be in any form (even by the trade from the previous installments through Pokemon home).
Remakes: Pokemon Fire Red & Leaf Green Games 2004 for GameBoyAdvance, on the Gen3 (Ruby & Sapphire) engine, a remake of Gen1 games. The same game with the same storyline, region, but all Pokemon r2-3 added, plus post-game content and new islands next to canto.
Pokemon Heart Gold & Soul Silver games of 2009/2010 for Nintendo DS, on the Gen4 engine (Diamond & perl), a remake of Gen2 games. The same game, with the same plot, region. Added pokemon r3-4.
Pokemon Omega Ruby & Alpha Sapphire 2014 games for Nintendo 3DS, on the Gen6 (X & Y) engine, a remake of Gen2 games, remade more significantly, plus added pokemon r4-6.
Pokemon Let's Go, Pikachu & Eevee - the 2018 games for the Nintendo Switch, on the new? engine, a Gen1 remake that includes only Pokemon Gen1 plus two new ones for the series, bringing the total number of Pokemons in all major game series + spinoffs to 809 at the time of the creation of the theme (02/28/2019).