Uhh, here are a few that I remember off the top of my head:
- The 45-45-90 triangle is also isosceles, due to the two 45-degree angles it has. However, the 30-60-90 triangle is scalene.
- The 45-45-90 triangle is half of a square (to see this, stick two copies of it together at their hypotenuses), while the 30-60-90 triangle is half of an equilateral triangle (join two copies at their longer leg).