As the comparisons demonstrate, ReShade's injectable post-process SMAA is the best post-process anti-aliasing solution for Rise of the Tomb Raider. It anti-aliases edges far better than SMAA, as is particularly evident on the laptop, desk and lamp, and doesn't blur textures like FXAA.
Setting ReShade SMAA up is pretty simple: download the ReShade app, extract the archive, open Mediator.exe, follow the steps in the readme to add Rise of the Tomb Raider, click on the "Pipeline" tab, untick everything other "SMAA - SweetFX", click "Apply", switch back to the "Setup" tab, save or update your preset, and click "Permanent Push To Application". Now start Rise of the Tomb Raider, configure your options in the launcher to disable anti-aliasing, and load the game. If you've done everything correctly you'll see some ReShade info on the top left of the screen, and have SMAA anti-aliasing similar to that shown in our screenshots.
You can then tweak the SMAA options in Mediator on the SweetFX > SMAA tab, and make further changes to the game's appearance through the many other included options. Alternatively, download other people's ReShade profiles from here.
Performance: As detailed earlier, SSAA can have a significant performance cost, similar to the cost of increasing the rendering resolution. That turns out to be 13 FPS for 2x SSAA, and 21 FPS for 4x SSAA, which pushes our reference-speed GeForce GTX 980 Ti below 30 FPS. If you have a SLI setup though, SSAA is a viable option. The newly-added SMAA, meanwhile, runs about a frame per second slower than FXAA, despite its poor coverage. And ReShade SMAA is that bit slower, though definitely worth it in our opinion.