Currently looking for help with those things.
This is absolutely not a complete list (there a millions of other things to do, see Issues and docs/TODO.txt), those are merely some suggestions of things I am particularly struggling with before I may not have the hardware or expertise. If you are motivated and want to help this project and the community there is almost certainly a spot for you :)

Funding

• If your company uses Dear ImGui, please reach to [email protected].

Community

• If you have experience with Dear ImGui and programming, helping people out on the Discourse forum would be very useful.
• Helping to answer in the GitHub issues/threads is very helpful too!
• The wiki needs improvements!

Third-party Software
If you are familiar or interested in GLFW, designing/developing/submitting those changes to GLFW would be extremely helpful to imgui:

• Linux/Mac: implement per-OS workarounds for other GLFW/SDL issues, see https://github.com/ocornut/imgui/issues/2117#issuecomment-465185644
• GLFW: Solve https://github.com/glfw/glfw/issues/1236 in GLFW (transparent inputs) for portable multi-viewport support. OR implement per-OS workaround in imgui_impl_glfw.cpp. Done PR: https://github.com/glfw/glfw/pull/1568, Waiting for GLFW merge.
• GLFW: implement/solve https://github.com/glfw/glfw/issues/427 in GLFW (add missing diagonal resize mouse cursors).

Features

• Viewport: The multi-viewport feature needs users/testers to move forward! (see #1542, available in docking branch`).
• Viewport: In particular, Linux/OSX have issues and need some work from volunteers. See #2117.
• Tables: Feedback wanted! See #2957.
• Docking: Feedback wanted! See #2109.

Platform/Renderer Bindings

• Mac: imgui_impl_osx.mm need some love (#1873)
• Mobile: Wanted imgui_impl_ios.cpp Platform Binding+Example for iOS (+ use existing renderer).
• Mobile: Wanted imgui_impl_android.cpp Platform Binding+Example for Android (+ use existing renderer).
• Web: Wanted imgui_impl_emscripten.cpp Platform Binding+Example for Emscripten (+ use existing renderer to create a new example). (#336)
• Viewport: Vulkan bindings needs to fix multi-viewport support (see Viewport branch and #1542): currently has Present issues.
• Viewport: Metal bindings needs multi-viewport support (see Viewport branch and #1542).

External Language Bindings

• Many language bindings are not kept up to date (see https://github.com/ocornut/imgui/wiki/Links)
• Considering switching bindings to use the cimgui generated data so users of your framework/language can stay up to date without manual intervention.