I saw the a few people posted the use case, FUD and also their pros and cons. Well I thought that knowing what a coin or it's dev team has on their roadmap for future can be a useful piece of information in making decisions about investment. Some coins/tokens really aren't having any future updates so their current/most recent update is therefore listed.

The "Top 20" is from coinmarketcap rankings. I am not trying to make a statement that top 20 mean the 20 greatest or my perspective. These were the top 20 at the time of posting on coinmarketcap. I also suggest you to consider this a concise/one line version describing the upgrade. For more details, I recommend you look up the internet based on the information below.

Top 20 CryptoCurrencies and their upcoming/recent updates:

1. Bitcoin (BTC) : Bitcoin network is expected to have the "Schnorr signatures". This solves some issues with privacy and scalability. This upgrade if passed, is expected to lower bitcoin transaction fee and also improve privacy of the holders. It also paves the way forward for Lightning network and Coinswaps.
2. Ethereum (ETH) : The EIP-1559 is the next intended upgrade to the ETH network. It revamps the GAS payment methods. Instead of auction type GAS payments, it introduces BASEFEE methods. It is expected to make GAS fees "predictable" but might not have a great effect on reducing the fee. It also introduces a deflation to ETH tokenomics as BASEFEE paid is burnt. And of course ETH 2.0 too but it's bigger to discuss here.
3. Cardano (ADA) : Cardano currently launched the mary update to allow multi assests on the cardano network. It is part of the "Gougen" era of cardano, which plans to introduce smart contracts and DeFi just like ETH to ADA network and unlike ERC-20 standard, cardano is trying to implement native ledgers for these multi asset tokens.
4. Binance Coin (BNB) : BNB is the native token of the Binance Smart Chain(BSC). Currently, the news/update is that new DeFi platforms like existing PancakeSwap are being developed on it and also 1Inch has extended support on BSC. Little is known about any distant updates as only source for news is either CZ or Binance themselves.
5. Tether (USDT) : Tether recently settled their lawsuit about the "lie" of having a stable token with backed assets. They are going to pay $18.5 Million in penalties.
6. Polkadot (DOT) : Parachains, the building blocks of the polkadot network are currently in the "rococo" phase and parachains are on test networks. Once they are tested, they'll be rolled onto the kusama network which helps devs see real network effects which aren't available on general testnets. When they pass on kusama too, we'll see first good parachains launch on DOT network via governance.
7. Ripple (XRP) : Ripple is still fighting with the SEC regarding the "unregistered security" case and many exchanges have an approach of wait till it settles and make a move. Co ordinated buying attacks have happened . Although SEC has strong evidence, it is being viewed as an overkill attempt to regulate crypto and is believed to just be FUD. You figure what is what…
8. Chainlink (LINK) : Chainlink has launched OCR "Off chain reporting" to their mainnet. What it does is it increases the amount of data oracles on network can bring on chain to 10x and 90% reduction in on chain costs according to Chainlink's Sergey Nazarov. More data output means more data can be brought on chain by DeFi which means more innovation on network.
9. Litecoin (LTC) : Litecoin is getting closer to launch it's MimbleWimble upgrade. It brings the feature of "opt-in" privacy to transactions and increases scalability. The date of launch is believed to be at around March 15.
10. Bitcoin Cash (BCH) : Bitcoin Cash will undergo an upgrade at around May 15th. I am not familiar with BCH and I was unable to find any official source on what the upgrade will be except from discussion and personal views. I'd be happy if anyone suggested an edit here.
11. Stellar (XLM) : After announcing samsung intergration in july, the crypto exchange and finance firm Abra announced that they'll be introducing traditional finance like banking to people without crypto knowledge on the XLM Blockchain. And Ripple battling SEC, XLM is expected to see adoption as both XRP and XLM initally wanted to serve the payments segment of crypto.
12. USD Coin (USDC) : After launching USDC on the Stellar network, the Floating Point Group (FPG) now is bringing USDC onto the Algorand network as USDCa. It aims to streamline and increase the capital efficiency for institutions compared to conventional transfer.
13. UniSwap (UNI) : The DEX Uniswap is expected to have an upgrade to UniSwap v3. The tokens swaps in native forms are raising gas prices. An L2 solution is expected which is rumoured to be zk-Rollups that take the work off chain. Liquidity mining is also expected to have new farms and also a better UX for users.
14. NEM (XEM) : On March 15, NEM will transition from N1S1 to Symbol. Symbol is described as a “trusted, secure value exchange network for business. Symbol smooths business friction, increasing the flow of data and innovation to supercharge the creation, exchange and protection of assets.
15. Dogecoin (DOGE) : Dogecoin recently had a recent core upgrade 1.14.3. It made significant improvements to the speed at which a node can upload blocks will be made by removing expensive integrity checks which were previously carried out each time a block was sent to another node after the update is applied.
16. Wrapped Bitcoin (WBTC) : It is a wrapped version of BTC on ERC20 and I wasn't able to find any upgrades. I would be happy if someone suggested an edit here.
17. Aave (AAVE) : Aave and Balancer recently announced their partnership. under the partnership a part of each liquidity pool on Balancer will become available to deposit on Aave, where it will facilitate lending. This process will be controlled by Balancer’s asset manager, which automatically supplies tokens to Aave when they are not needed in the pool.
18. Cosmos (ATOM) : Cosmos recently upgraded to Stargate. Stargate represents an important milestone for the Cosmos project on the way to launching its inter-blockchain communication (IBC) protocol that will allow the 200+ Tendermint-based blockchains to interoperate easily. It also brings some features, the chain will run more efficiently, upgrades will be much faster and full nodes will be able to sync up more quickly.
19. Monero (XMR) : The Monero devs are working on making Monero more easier to use. The current most awaited feature in XMR space are the atomic swaps. Atomic swaps allow users to swap between BTC and XMR smoothly on a single DEX. This might not sound incredible, but it is. As exchanges crackdown on monero trading…it's difficult for people to buy and sell XMR. With atomic swaps, they can in future just convert from XMR to BTC and trade.
20. Solana (SOL) : Raydium, the first AMM(Automated market maker) on Solana Blockchain was launched on Feb 22. The release of Raydium helps to bring the SOL ecosystem one step closer to being a viable competitor for DeFi on Ethereum.