ArXivLens has multiple features to look for preprints in ArXiv.
The app inludes all the subjects and categories you find in ArXiv.
You have a search history to reuse your old searches and find new results.
The app opens pdf preprints from your results with an external application.
The app allows to mail to your coleagues or friend with a link to your search.

About Arxiv*:
The arXiv is a repository of electronic preprints, known as e-prints, of scientific papers in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance, which can be accessed online. In many fields of mathematics and physics, almost all scientific papers are self-archived on the arXiv repository.

*From https://en.wikipedia.org/wiki/ArXiv