As a designer myself, I often have to find logo mockups to showcase my work to clients. Sometimes, the client just can’t see how the logo will look like on a white canvas. I often showcase my design ideas using mockups because they look realistic and convey a much better design understanding.
In my 10 years of graphic designing experience, I have come across a bunch of mockup designs. There are plenty of well-designed mockups available online but the best ones often get buried in Google search results.