VMware vSphere is described as 'The vSphere Web Client enables you to connect to a vCenter Server system to manage an ESXi host through a browser' and is an app in the Network & Admin category. There are more than 10 alternatives to VMware vSphere for a variety of platforms, including Linux, Online / Web-based, Self-Hosted solutions, Mac and Windows. The best alternative is VirtualBox, which is both free and Open Source. Other great apps like VMware vSphere are Proxmox Virtual Environment (Freemium, Open Source), OpenStack (Free, Open Source), VMmanager (Paid) and oVirt (Free, Open Source).
oVirt is a virtualization management application. That means that you can use the oVirt management interface ( the oVirt engine) to manage hardware nodes, storage and network resources, and to deploy and monitor virtual machines running in your data center.
XO is a web UI providing a simple and nice web interface to manage XCP-ng and Citrix Hypervisor (formerly (XenServer) infrastructure (VM, servers, pools, etc.). It's also a fully feature backup solution for those platforms.
Danube Cloud is a cloud management software used for deploying, maintaining and automating cloud data centers and their processes. The project aims to simplify the whole server virtualization environment by automating all the repetitive tasks for the system administrator.
Multipass is a lightweight VM manager for Linux, Windows and macOS. It's designed for developers who want a fresh Ubuntu environment with a single command. It uses KVM on Linux, Hyper-V on Windows and HyperKit on macOS to run the VM with minimal overhead.
WebVirtMgr is a libvirt-based Web interface for managing virtual machines. It allows you to create and configure new domains, and adjust a domain's resource allocation. A VNC viewer over a SSH tunnel presents a full graphical console to the guest domain.