Look for sign flashers, they are designed to do that, so you get a module with a simple capacitive power supply, a 555 timer and a 4017 chip and selectable 2 to 4 outputs, with each being a 16A triac as switch, using some zero cross switches to drive them. Typically limited to 5A total by the fuse, as the traces are not going to survive more.
Otherwise a Faraday motor sign switch is totally electrical and mechanical, using a homopolar or eddy current motor, as a slow drive for a set of large mechanical switches on an eccentric cam. Those run for decades on 27/7 with almost no maintenance.
If you want good incandescent lamp life simply connect the primary of 2 small transformers ( secondary voltage irrelevant as you only are using the primary magnetising current) of around 10VA rating across each relay, to provide a small current flow in each lamp so the filament stays warm when off. NTC in the supply lead as well to limit cold inrush on initial switch on so the cold lamps warm up slower. Only works with relay drive, but a relay will easily do 100 million cycles mechanically if you are running it at low current, so use a 10A rated relay, preferably a 24VDC one, to drive your 100W lamp load. Use a plug in Omron one, so you can change it easily, and use the NO contacts only on the relays, do not rely on the CO contacts providing a good lifetime, as the NO contact is rated better than the NC contact.