CEmu is a free and open-source third-party TI-84 Plus CE / TI-83 Premium CE calculator emulator, focused on developer features.
The core is programmed in C and the GUI in C++ with Qt, for performance and portability. CEmu works natively on Windows, macOS, and Linux.

GitHub repo: https://github.com/CE-Programming/CEmu/

Standard features
Built-in ROM dump wizard. CEmu does not rely on downloading an OS from TI's website nor does it have a custom boot/loader: a ROM from your own calculator is required. CEmu makes it very easy to get it.
Accurate and fast emulation (you can also customize the speed and even toggle throttling)
Resizable calculator screen
"Always-on-top" window option
Screen capture, copy, and drag'n'drop (PNG)
Screen recording (animated PNG)
File sending/receiving (not for Apps/OS yet)
Customizable keybindings with multiple presets
Keypress recording and history
Full screen modes (F11 key)
Emulation states for efficient saving / restoring
CE skins (colors like the real devices)
Available in English, French, Spanish, and Dutch

Developer features
Main options available via CLI arguments
IPC features when launching several CEmu processes
Import/Export RAM, ROM, images...
Custom display refresh rate, FPS indicator
Custom emulation speed/throttling
Rich text console for easier logging/debugging
Code stepping, jumping...
R/W/X breakpoints, watchpoints
eZ80 disassembler (with equates support)
Port monitor/editor
General Timer monitor/editor
Memory viewer/editor
CPU state/registers viewer/editor
LCD state/parameters viewer/editor
Memory visualizer (as fully customizable virtual LCDs)
Stack viewer
OP1-7 viewer
FP and OP stacks viewer/editor
Variable Allocation Table (VAT) viewer
Variable list with preview and program launcher
TI-Basic program viewer with syntax-highlight and reformatting
Recent files list with ability to quickly resend
Cycle counter for benchmarking/profiling
Emulation of DMA and SPI (for optimal accuracy)
Misc. emulation (backlight, battery...)
Pre-I HW Rev. emulation toggle (IM 2 compatibility)
"Autotester" (automated unit testing, light scripting)