Insteon components can be used stand-alone without a hub.
Purchase any combination of dimming plugin module, on/off plugin module, or duplex outlet (dual control-each outlet can be controlled separately or linked together).
Replace a wall switch and link it all together manually. You will get exactly what you asked for, the ability turn on/off one switch and have multiple things turn on/off. You can also add many more devices (now or later) than you will ever need... you can keep it super simple or make it very complex.
Manual linking does work, but is a tedious process with a learning curve. You can also add a hub which gives you all those things you don’t want, like internet, schedules, remote from your phone etc etc. but with the added advantage of more simplified setup. (No manual linking -much easier to do linking with hub). AND once the modules are setup (I.e. linked or programmed) the hub can be unplugged and put away and it all continues to work standalone without the hub. I mention that because there are bundles and starter kits that make the hub essentially free.
Not obvious to newcomers: 1) Insteon and smarthome.com have the same owner, it’s always least expensive to buy direct from smarthome.com 2) smarthome has lots of sales and promos, never pay the regular website full price. Also don’t miss the multi-packs that also save. 3) many items are available on amazon but mostly avoid it, some of the product has really old date codes and firmware when purchased through amazon.
Many Insteon items are available in other electrical standards than USA. Such as European, although it’s easier to see compatibility from the country in question, the US site doesn’t show all international product. See here for more international purchasing options.
Disclaimer: I don’t work at smarthome/Insteon. I just have a huge complicated Insteon system with over 100 switches and modules. (The only two non-Insteon switches in my house both control garbage disposals.)