The 1.5.0 version of redream for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The application lies within Games, more precisely Tools. The actual developer of this free software for Mac is Recompiled LLC. We recommend checking the downloaded files with any free antivirus.
From the developer:
Redream is a Dreamcast emulator that lets you experience the Dreamcast in HD. With this tool, you can render your favorite Dreamcast classics in 1080p or 4k as they deserve. You won't need controller configuration, BIOS, or flash files - you just add games and play. Over 85% of the Dreamcast's library is able to be played from start to finish.
You may want to check out more software for Mac, such as Map Editor, PPF-O-Matic or Generator, which might be similar to redream.