Just bought some coloured switches and sockets from
Guan Seng Electrical Service Co at Woodlands Horizon, 31 Woodlands Close, #01-07, S737855.
Have been looking for black switches and sockets for some time and managed to find it here at contractor price. They have them in grey, silver and white colour too. Hopefully, this is useful for those who are looking for coloured switches and sockets.