I have tried a few electric heaters but they are not strong enough. My electric stove emanates more heat that those portable electric heaters. So Perhaps I am not looking for the right thing. What is the right heat measure for indoor radiant infrared/ceramic heaters (without fans)? (regardless of energy efficiency) and can they be used on normal outlets.
Well stoves aren't space heaters. Remember that.
If you think your stove heats better, its probably due to your stove having 50 AMPS at 240V available to it. That' 12,000 watts.
Any portable cheap electric space heater that you can plug in to mere common outlets will be limited to 1800 watts, but more often 1200 or 1350.
It's about the amount of energy available
Stoves have bigger wiring, bigger outlets, and access to more power.
In contrast my home electric furnace is hard wired and can draw up to 28,800 watts with an additional 2500 via the heat pump.
What it comes down to is this...
Heaters gonna heat
Install an appropriately sized heater. If you want more heat you should buy one with a higher wattage rating, and it will probably need to be hardwired. Don't use your stove for heating.
Power (heat) is measured in watts. A heater with a higher wattage will put out more heat than a lower wattage heater. In the USA, most portable heaters will be limited to around 1500 watts due to typical 120V/15A home wiring. Permanently installed electric heaters are often higher.
Note that a single large electric stove burner could well be more than that: up to 3000 watts. This is possible due to the special wiring that is necessary for stoves (more amps) and 240V instead of 120V for most other household outlets.
Also all electric heaters have essentially 100% efficiency, so that should not be a meaningful comparison point.