U.S. regulators on Wednesday added separate filings to their docket for a proposed Solana exchange-traded fund and a rule change that would allow the listing of an investment product tied to Pudgy Penguins tokens. The Invesco Galaxy Solana ETF joins a list of eight other funds that would track the performance of the sixth-largest crypto by market capitalization. Meanwhile, a 19b-4 request by Cboe would allow the Canary PENGU ETF to trade on the exchange. The filings are among the latest developments in an increasingly heated crypto ETF space, which has intensified since the dramatic success of spot Bitcoin and Ethereum funds over the past 18 months, and amid a more receptive political environment for crypto products. The SEC is weighing more than two dozen applications for altcoin-based ETFs, including not only Solana but XRP, Dogecoin, Cardano, Polkadot, and Hedera. Earlier this month, seven Solana fund issuers filed amended S-1 forms with the SEC, clarifying language that would enable them to stake the Solana they hold. Staking refers to the process of pledging tokens to a decentralized network in exchange for yield, or financial rewards.  Its inclusion in ETFs is a point of contention among federal regulators, who previously delayed their decision on staking in Ethereum ETFs due to concerns over the financial and security-related risks posed by the practice. Solana, XRP, and Litecoin spot ETFs are near locks at 95% odds of approval from the U.S. Securities and Exchange Commission by the end of 2025, according to estimates last week by analysts Eric Balchunas and James Seyffart of Bloomberg. Dogecoin, Cardano, Polkadot, Hedera, and Avalanche spot ETF applications have a 90% probability of approval by year-end. Such altcoin funds seemed unlikely until the success of the BTC and ETH ETFs, which have generated $47 billion and $4 billion in net investments, respectively. The Invesco Galaxy Solana ETF will  trade under the QSOL ticker. Galaxy Digital Funds will serve as the fund's execution agent, purchasing and selling SOL on behalf of the fund. Coinbase will serve as the fund's custodian. Crypto-focused investment management firm Canary Capital filed for its Pudgy Penguin fund in March, one of several other altcoin ETFs that it has proposed to the SEC. Solana, the native token of the Solana network, was recently trading at $143, down nearly 1% over the past 24 hours. It has declined by roughly 18% over the past month, as most altcoins have experienced a downturn. However, it remains a favored blockchain among many developers due to its speed and efficiency. PENGU was roughly unchanged from Tuesday at the same time and has fallen 22% over the past month. Edited by Sebastian Sinclair