Smart Rules are additive, not alternative: every rule you add to an offer must pass for the offer to show, so adding a second rule only ever narrows an offer's audience further, never widens it. There's no "any of these" grouping across different rule types — if you need that kind of either/or logic, it isn't a single-offer configuration, it's two offers with complementary rules.
The 25 available rules fall into five groups. Cart Contents rules (cart products, collections, specific variants, product tags, cart attributes, and two subscription-specific rules) look at what's physically in the cart right now. Cart Value & Quantity rules target a dollar range, a value-conditioned range, or an item-quantity threshold. Audience rules — markets, shipping country, retail location, customer tags, Klaviyo segment, language, device type, B2B/wholesale status, and customer province — target who's shopping rather than what they're carrying. Trigger rules (specific products or collections) are unique to the product-page context, since they're the only rules that reference the page being viewed rather than the cart. Context rules cover scheduling, discount-code presence, and traffic source.
Most rules support both an include and an exclude list rather than one or the other, which is what lets you write "show this to customers tagged VIP, except in these excluded markets" as a single rule rather than two.