U2-Net by Xuebin Qin and contributors, Apache-2.0. Lightweight U2NETP model exported to ONNX and distributed by rembg.
Source: https://github.com/xuebinqin/U-2-Net
Model: https://github.com/danielgatis/rembg/releases/download/v0.0.0/u2netp.onnx
SHA256: 309c8469258dda742793dce0ebea8e6dd393174f89934733ecc8b14c76f4ddd8

Full U2NET model, same authors and license.
Model: https://github.com/danielgatis/rembg/releases/download/v0.0.0/u2net.onnx
SHA256: 8d10d2f3bb75ae3b6d527c77944fc5e7dcd94b29809d47a739a7a728a912b491