When looking to miter two long pieces together for a TV stand, it seems the popular option is a spline for strength (which also gives a nice look with a contrasting spline material). However, since I don’t have a table saw I looked for other options. (I did see some people make jigs to use their circular saw to make perpendicular splines, but that seemed too hard.)
Festool Domino
For those with a big budget (not me!) the Domino Joiner seems to be the tool of choice. It’s ability to create mortises quickly at angles from 0 to 90 degrees makes joining much quicker. However the $1,060 price plus tenons is out of my price range. Most kits are around $1,400.
Biscuit Joiner
Many people use a biscuit joiner for aligning boards together. But in general they are not well suited to miters as they don’t provide any strength, only alignment help.
DowelMax Jig
I ended up buying the DowelMax classic jig along with the 45 degree miter accessory. At $225 for both (during the current sale) it’s 1/5 the price of the Domino. While it’s not as fast to setup and use, the joints are strong and it works well for my use-case. There are certainly others like the Jessem dowel jig but I didn’t see a miter accessory for it.
Overall I’m happy with my purchase as my woodworking budget grows I’ll certainly try the other methods such as splines, or maybe I’ll splurge on the Domino one day, but for now this works well.