I think that if there is a black friday deal, it's already there and I don't expect a surprise from any company in 29 November, so it's fair to say that Mullvad and IVPN don't offer any Black Friday discount.
Proton VPN has a good discount, 1 year plan worth $35.88. This is the link of their Black Friday deal: protonvpn.com/blackfriday
Windscribe also has a nice offer, 1 year worth $29. For this Black Friday deal, visit:
https://windscribe.com/upgrade?promo=FUCHYEAHGhostVPN offers 2 years for $60, here is the link to the deal:
https://www.cyberghostvpn.com/buy/cyberghost-vpn-3ExpressVPN gives you additional 6 months free, so, 30 months plan costs 149,70 USD, link to the deal:
https://www.expressvpn.com/order-deals-trialNordVPN also offers you multiple plans, so check the deal yourself:
https://nordvpn.com/pricing/Surfshark has multiple deals, so it's better to check plans yourself:
https://surfshark.com/pricingIt's expected Mullvad wouldn't offer Black Friday discount. After all, they always offer flat 5 EUR/month with 10% discount if you pay with cryptocurrency. Deal by Proton VPN isn't half bad either, although it's Proton Unlimited (where you also get email, drive and others) is better choice if you really trust Proton with all kinds of tasks.