Can you clarify if you mean something else when you say genome browser? IGV or IGB are not in your list.

@dariober's ASCIIGenome: https://github.com/dariober/ASCIIGenome

Many in the current suite of browsers make you sit and wait for data to come in and get rendered. WebGL-backed HiGlass and Valis may be contenders for where browsers are headed or need to head.

I have used HiGlass for a couple projects. It supports various dataset formats and is extensible. One way to think about HiGlass is like Google Maps for genomic data.

Not sure how much of the commercial Valis project is open-sourced, but I think ENCODE has used it or its commercial counterpart. It is similar to HiGlass conceptually, but has its own look and feel.

Edit, March 24 2021

Speaking of WebGL-backed 1D/2D genome browsers, Kari Lavikka will be giving a VIZBI talk later this week on his WebGL-based GenomeSpy project.

It looks very sharp and also introduces concepts in the Vega data visualization grammar. The Gehlenborg lab and collaborators in their Visual Encoding project are also working on dataviz grammars.

GenomeView is also free to use (not sure if completely open source) and I kinda like it, does viewing as well as editing (very few do offer the editing these days)

I'm a big fan of JBrowse. I prefer it to the likes of IGB and IGV because of the much faster loading times for big BAMs. It also allows you to structure information for users so they can explore data integration.

I haven't tried JBrowse2 yet, but its on my list and brand new in 2020.

I always use IGV to quickly check my data locally because it is quick, it has some powerful features, and I'm used to it.

But if I need to set an online genome browser for collaborators, my preference goes to the Washu epigenome browser. It is intuitive, supports a lot of different file types, there are multiple ways to easily save sessions (through files or links or names), it has nice features (for instance split screens), and the design is minimalist by default, which save time cleaning things up (hello UCSC and your thousands vertical lines).