Supported servers

Users have reported that it works on the following official servers:

iRO (international). Sakray and Iris included.
mRO (Malaysia)
inRO (India)
pRO (Philippines)
idRO (Indonesia)
oRO (Oceania/Australia)
vRO (Vietnam)
euRO (Europe)
bRO (Brazil) - only supported when you also have KoreGuard (a third party product, not directly associated with VisualKore)
tRO (Thailand)

Users have also reported that it works on these private servers:

AnimaRO
XaosRO
aeRO and aeRO2
powRO
SonicRO
ExcaliburRO
AvalonRO
ChocoRO
RuRO
AniRO: Chaos

Unsupported servers

Users have reported that the following servers are not supported:

The Redemption Online private server.
The VanRO private server.
NamelessRO (Eclipse and Sunrise)
dutchRO
FlyRO (www.flyro.net)
RO-Hispano
FunRO
Ragnarok Frontier
XileRO
PSIBlade

Other official servers

It's not known whether other servers are supported because no users have reported anything about them.

Other private servers

VisualKore will probably work on most Aegis-based private servers. If your private server is based on eAthena SVN or Freya, then VisualKore might work, depending on the server software's version.