In Pokemon Conquest for the Nintendo DS, there are cheats you can enter to force swarms of pokemon to spawn.
In order to use these, you must control at least five kingdoms.
To enter these, tap the Menu button and select Password. Type in the password below to force that pokemon type to spawn in the following game month somewhere in your kingdom.
Axew – BqWxXEK3xg
Beldum – cMqkZRRSRX
Cincinno – vVALFrGTXX
Darmanitan – pK5RgzqLG8
Dratini – Sr5Z5GqAgR
Eevee – 2rz3XFCKmR
Emolga – Jnm3kqgN8X
Gible – LTb3n3RYJ8
Gyarados – mq2xRVNgRL
Lapras – GfV33RVN3F
Larvitar – Lpu3ggCYk8
Oshawott – frCLRpXG88
Panpour – CNZF3wpq3x
Pansear – niE33w9rwM
Pikachu – FZP8GqRZRR
Riolu – Shw8mxRAJR
Schyther – 8GV3LMGrnM
Sneasel – Rc338MpqLx