1. The EZ Fires you're familiar with.
2. Twist shifters.
3. Friction shifters.
4. Thumbshifters.
5. Dual Control.
6. SRAM Double Tap.
7. Shimano's road 'brifters'.
SRAM's Impulse triggers are an improvement over Alivio trigger design, but they're still triggers. SRAM was/is also the innovator of the twist shifters.