I use BetterTouchTool with Vivaldi to add a pair of buttons to my Touch Bar that switch left or right in the tab bar. As someone who typically has a pathological amount of tabs (I do a lot of research), this is a near-necessity for me. It lets me move on the tab bar quickly, with ctrl-tab for a tab cycler in most-recently-used order.
As far as I can tell, the only way to do this on Orion is to use the system keyboard shortcuts for "Show Previous Tab" and "Show Next Tab." Unfortunately the behavior of these options is tied to the "Use Tab Switcher" and "switch tabs using" options in Orion's settings - if I have ctrl-tab switch to the most recently used tab, the two menu items for that bring up the tab cycler instead of moving left and right.
This seems easy to implement, and it'd be useful for faster and more intuitive browsing.
Would allow users to keep track of portions of the tab bar that are related to specific subjects, in my case. Would presumably fit well into other folks' browsing flows depending on how they use the browser. Vivaldi (my current browser, and slow) allows independently setting a keyboard shortcut to move tabs left and right.