On alternate type triangles.

As we have another generation coming, the endless debate of replacing the type triangle has begun again.

So, let's cover alternate type combinations, then:

Known triangles:

1. Fire/Water/Grass- classic.
2. Fighting/Dark/Psychic- Thief, Mage, Fighter triangle. Not mechanic, but thematic.
3. Ice/Steel/Rock- Golem triangle. Somewhat mechanic, with Steel being a sub-leader.

Other triangles:

1. Ground/Water/Flying- Geo-sphere triangle. Weather trio is this.
2. Fire/Ice/Electric-Legendary birds and Tao trio
3. Grass/Rock/Steel(/Water)- Muskedeers.
4. Electric/Flying/Ground-Kami trio
5. Steel/Water/Ghost-Creation trio
6. Dragon/Dark/Fairy-Kalos trio.
7. Fire/Water/Electric-First Eeveelutions and Legendary beasts
8. Steel/Ghost/Dragon-Nebula trio.

Other notable stuff:

-DP starters had secondary typings that gave them advantage over their enemies. Fighting over Steel, Ground over Fire, Steel over... nothing actually. But we can say Ice instead of Steel due to Empoleon's theme.

Edit(25.01.19): Edited the notable stuff part and added Nebula Trio.