One of my favorite @Vivaldi features on computers is single key keyboard shortcuts. This feature is turned off by default, but once enabled, you can perform functions with a single key.
Here are a few shortcuts:
Z - back
X - forward
9 - zoom out 10%
0 - zoom in 10%
6 - reset zoom
WASD - spatial navigation
This is an advanced feature, so only enable if you love using the keyboard!