The Heifer international jumping cow is an logo that has the cow jumping over the name of the foundation. The cow is simple and it can be used anywhere and look appropriately formal or informal. A friend of mine actually used the Heifer International cow in her wedding invitations because she wanted people to donate to Heifer rather than give gifts.
The MIGHTY MONARCH! I love this logo. It is the symbol of a super villain on an adult cartoon called The Venture Brothers. The logo is interesting because it looks powerful and has the monarch's crown on the butterfly's head. The butterfly has slanted triangular eyes that look angry. Despite the strong red image the actual character is kind of a wimp and typically oversells the looks and under-delivers the evil.