• Misleading defaults and prechecked boxes: Auto-enrolling customers in subscriptions, add-ons, or insurance by default so they must actively opt out.
• Hidden costs and bait-and-switch: Showing low prices then adding fees at checkout or displaying a product as “in cart” with higher price to pressure purchase.
• Scarcity and urgency tricks: Fake countdown timers, low-stock warnings, or “only X left” messages to rush decisions.
• Obstructive opt-out and cancellation: Making unsubscribe or cancel buttons hard to find, requiring phone calls, or adding many steps to stop recurring payments.
• Forced continuity: Free trials that silently convert to paid subscriptions without clear reminders or simple cancellation.
• Confirmshaming and nagging: Guilt-inducing language (“No thanks, I prefer losing money”) or repeated pop-ups that interrupt browsing.
• Misdirection and cluttered layouts: Emphasizing a preferred CTA (e.g., “Buy now”) with bright color while hiding safer/cheaper options in muted text.
• Social proof manipulation: Fake reviews, falsified sales counts, or fabricated user endorsements to create false trust.
• Hidden data harvesting: Ambiguous consent controls that collect extra personal data for marketing or sharing with partners.
• Roach motel: Easy to sign up but hard to leave—subscriptions, loyalty programs, or data-sharing agreements that are simple to enter and difficult to exit.

References: Brignull, H. “Dark Patterns” (darkpatterns.org); Mathur et al., “Dark Patterns at Scale” (CHI 2019).