Newer cricut user here, so I’m far from an expert but I’ve found https://freesvg.org to have the best free selection of all the sites I’ve tried so far. Source: over 1 year ago

Contextually, what you're doing is fine. You're making personal-use invites for a kid's birthday party so I think it's admirable you're hoping for some casual free resources for use. Generally speaking, you're going to likely be looking for each source on a case-by-case basis because there isn't a single go-to large repository of commercial-quality, diverse free libraries of content. Some get close but they won't... Source: over 1 year ago

Freesvg.org and Vecteezy for illustrations/clip art. The cover of Project BRKN-Shackle uses two versions of the same “spy” graphic, and I then modified it/shifted the colors. I did even less work on Playdate Peril’s cover, just combining a couple illustrations. Source: almost 2 years ago

Not CorelDraw, but I think you can use this site for free SVG's. https://freesvg.org/. Source: almost 2 years ago

What you need is svg files, you can edit them using inkscape, which is free: https://inkscape.org/ There are lots of free public domain svgs here: https://freesvg.org/. Source: about 2 years ago

Barn Images provides a collection of high-quality, free stock photos of barns and rural landscapes. The website was created in 2014 by two photographers who wanted to offer a unique collection of free pictures for creative projects. All the images on Barn Images are licensed under the Creative Commons Zero (CC0) license, meaning they can be used without attribution or permission for any purpose, including... - Source: dev.to / over 1 year ago

Barn images – Free high-resolution photos for everyone. Source: over 1 year ago