Single Push button on off relay Switch using 555 | One push on push off switch circuit testing - YouTube
TDBE series delay on & delay off timer relay for demanding applications, by Mors Smitt.
T40405 - 24V 10A Adjustable Delay On/Off Timer Relay [ALM Part Reference - T40405] - £31.47 : ALM Solutions, Auto Electrical Parts and Accessories for Cars, Boats, Caravans and Campers
GRT8-D On Off Timer Relay - ALION
Dc 12v Relay Wireless Remote Control Rf Switch On/off Switch +1 Channel Relay Delay Time Timer - Relays - AliExpress
220V 240V Relay, Briidea On/Off Switch Electric Heating Relay with Built-in 24V Transformer, Replacement for Any Relay, Compatible with 24V Thermostat - - Amazon.com