Ditto---Route 47
Snubull---Route 38
Dunsparce---Dark Cave
Remoraid---Route 44
Yanma---Route 35
Chansey---Route 13
Marill---Mt. Mortar
Qwilfish---Route 32
Wingull---Vermilion City
Poochyena---Route 1
Whishcash---Violet City
Swablu---Route 45
Ralts---Route 34
Buneary---Route 25
Luvdisc---Route 27
Clamperl---Route 19
Relicanth---Route 12
Kricketot---Viridian Forest
Sableye---Heartgold Only---Route 9
Baltoy---Heartgold Only---Route 3
I hope that helps everyone.
Unfortunately, there are no swarms on HeartGold and SoulSilver, only on Diamond, Pearl and Platinum.
You can catch them while they're in swarms. Otherwise it's almost impossible and will take you weeks non-stop. To get Pokemon in swarms you need to listen to the radio on your pokedex and wait for it to say where the snubull is swarming.
Ralts appear in 'swarms', you have to listen to the radio often until Mary announces breaking news where she will tell you were to go for ralts.
Snubull are usually found in swarms. Otherwise, they are really rare. Swarm locations and the Pokemon type can be found by listening to Professor Oak's and Mary's talk show on the radio.
There is no best Pokemon on Pokemon HeartGold.
there is no Pokemon Mansion in Heartgold.
They are not in Pokemon HeartGold
swarms on route 222
Route 14 swarms
They tell you where Pokemon are and where Pokemon swarms are.
where is the pokemon transfer lab in heartgold
You could find swarms of ralts on route 34 on the right day if you're lucky and then evolve it at level 20 or just trade for one somewhere