Go, Look: Independent On First-Reaction Nice Cartoons
Jess Denham at the Independenthas a round-up of initial cartoon reactions to Nice. One nice thing about the article is that it recognize a few older cartoons that have been re-used, and reaches into multiple distribution sources to find the cartoons upon which it comments. It isn't just Plantu.
A few of the news articles I've read have placed the horrifying incident at Nice in a continuity with the Paris attacks of late last year and the Hebdo office murders and subsequent manhunt-related violence from January 2015. I haven't seen this done in any way except for the criminality of the acts and their body counts, although that's not likely to remain the case and in times like these even inferences can be troubling.