Serena Williams is leaving tennis to become a full-time venture capitalist. Here are some of the investments she has already made, from a couples' therapy startup to an NFT wallet.

Lolli is a browser extension that lets users win rewards in cash or bitcoin when they shop at select websites. Some of Lolli's partners include StubHub, Staples, Sephora, and Nike. Lolli has raised more than $20 million in funding, according to Crunchbase. Williams' husband, Reddit co-founder Alexis Ohanian, also invests in Lolli through his own venture fund, 776.

MasterClass is an online education platform with classes taught by people who have found success in their fields. Examples include an inclusive leadership class taught by former President Bill Clinton, a science class taught by Bill Nye, and songwriting by Alicia Keys. Subscriptions to MasterClass start at $15 per month.

Tonal is a home gym system that offers streamable classes, similar to Peloton, but for strength training. Tonal is one of 16 unicorns, or companies valued at more than $1 billion, that Serena Ventures has invested in, along with MasterClass and Impossible Foods. Tonal's equipment costs $3,495, excluding accessories and membership.

OURS calls itself "modern" premarital and couples counseling. OURS offers live, virtual counseling sessions, along with content-based sessions hosted by the company's technology. "Research shows that relationships are the most important factor to our overall health and wellbeing, which is an area that I'm hyper-focused on in my personal life," Serena Williams said in a release announcing her investment.

Clubhouse is an audio-only social media app, where users can host or drop into "rooms," which are large group conversations. Clubhouse exploded in popularity in 2021, and has raised $110 million in funding, according to Crunchbase.

Daily Harvest is a subscription-based service that delivers healthy frozen foods and smoothies to your door. Daily Harvest says it freezes ingredients at "peak ripeness" to lock in flavor and nutrients. Menu options range from an avocado and greens smoothie to a portobello and pesto flatbread.

Infinite Objects says it "prints video." In reality, Infinite Objects sells a digital frame that allows customers to "frame" a loop of their their digital videos. The company offers NFT-holders a way to display their digital artwork in the physical world.

Hued is a digital healthcare startup aimed at addressing the needs to Black, Latinx, and Indigenous populations through education and access. The company was founded by Kimberly Wilson, a senior editor at Essence Magazine.

Banza is a line of chickpea-based gluten free foods, including pasta, pizza, mac 'n' cheese and rice. It's available for sale at a number of grocery stores including Whole Foods and Walmart.

Billie is a direct-to-consumer subscription razor company that says it aims to do away with the Pink Tax, which refers to when companies charge more for products marketed toward women. The company sells products like razors, shaving cream and body lotion, all for under $20.

Nestcoin says it aims to help people in Africa understand and adopt cryptocurrencies. The company builds and invests in crypto products, and recently launched Breach, a media platform it hopes will drive crypto education. The company has raised $6.5 million in funding, according to Crunchbase.

Bitski has been called the "Shopify for NFTs." Bitski is a a crypto wallet that lets people and brands create, sell and purchase NFTs. Shoppers can buy NFTs with just their credit card. The company not only counts Serena Williams as one of its investors, but also Jay-Z.

Fiveable is a free social network study platform for students. Students can create online study rooms with friends, and set study tasks to hold each other accountable. The company has raised more than $15 million in funding, according to Crunchbase.