Survey of Sombor-Type Degree-Based Topological Indices

The Sombor index is a graph invariant, defined as the sum over all edges uv (pairs of adjacent vertices u and v) of the term, where d(u) denotes the degree of the vertex u.It was invented in 2021.Since then, remarkably many of its variants were proposed and considered in the literature.This survey provides an exhaustive list of these variants, restricted to those that depend solely on vertex degree.