This is the current "version" of Ethereum. EthHub has extensive information and background on ETH1x.
A list of current working groups focused on core research, upgrades, and challenges.
Implementing state rent to address large and growing state. State rent is only one solution, so other facets are explored too - advanced snapshot sync algorithms, stateless clients, etc.
Using the ETH2 beacon chain to finalize ETH1 blocks.
Alexey is interested in seeing this happen, but doesn't have the bandwidth to lead this Working Group. Please comment in the EthMagicians thread if you want to get involved.
Discussion groups for at least one proposal (e.g. elliptic curve linear combinations).
Building a spec for Ethereum-flavoured WebAssembly (wasm) and determining what might go into ETH1x vs. preparing for ETH2.
Improvements to the current EVM around speed, safety, and interoperability. Safety improvements will increase the capabilities of static analysis and formal verification tools operating on EVM. Interoperability improvements include making EVM a better code generation target for higher-level languages like Solidity and Vyper, as well as lower-level bytecode formats such as WebAssembly/Ewasm and LLVM IR. Also helping form long-term plans for EVM across the ETH1x and ETH2 roadmaps.
Also known as EIP-1559, splitting gas fees that transactions are paying into two parts. One part gets burnt (destroyed), another - paid to the miners. In theory, this should make total transaction fees more stable and predictable.
Smaller initiatives around core systems and processes, calls for collaboration.
Ongoing infrastructure focus areas for coordinating work & support on the core network.