Middleware software for E1 interfaces

We're planning on modernizing our interfaces of E1 with other applications and hopefully add more interfacing to improve automation and less manual work.

Besides Mulesoft & Boomi, does anyone have any other suggestions on other middleware platforms that we should look at?

Currently looking to interface an external WMS SaaS application with E1, but the future applications to be interfaced is yet to be determined. For now, what we know is we're leaning more towards SaaS products.

Thanks.