Below is a curated list of top SEO and web development firms that frequently rank highly for B2B companies (SaaS, tech, manufacturing, professional services, etc.). I grouped them by primary strength (B2B SEO specialists vs. full-service web development / design + SEO). Each entry has a short note on why they’re a fit and a supporting citation.

B2B SEO specialists (best when you need deep organic search strategy, content, technical SEO)

• Omniscient Digital — Strong track record running enterprise and B2B SaaS SEO programs focused on revenue and growth. (alexbirkett.com)
• Siege Media — Content-first SEO agency known for scalable content + link acquisition that works well for SaaS and other B2B niches. (Link-Assistant.com)
• RevenueZen — Revenue-focused B2B SEO for SaaS companies (emphasis on lead attribution and conversion). (ziggy.agency)
• iPullRank — Enterprise & technical SEO expertise (good for large B2B sites with complex technical needs). (beomniscient.com)
• Directive — B2B & enterprise search marketing with experience in SaaS and technology verticals. (beomniscient.com)

Full-service / web development + SEO (best when you want design, development, and integrated acquisition)

• WebFX — Large full-service digital agency offering SEO, web development, and performance marketing for B2B clients. Widely cited in rankings for B2B SEO and web services. (onelittleweb.com)
• KlientBoost — Known for conversion-focused paid + organic funnels; offers landing/web development plus SEO/CRO for B2B. (onelittleweb.com)
• SmartSites — Full-service agency (design, development, SEO, paid) used by many B2B organizations and often listed in top agency roundups. (onelittleweb.com)
• Ten Speed — Boutique agency specializing in content, SEO strategy and site UX for B2B brands (good fit for growth-stage companies). (Link-Assistant.com)
• First Page Sage — Firms that publish B2B SEO rankings and lists; they’re also a B2B-focused SEO provider (noted in multiple 2024–2025 lists). (firstpagesage.com)

Specialist / niche agencies worth considering (for technical builds, enterprise engineering, or integrated B2B marketing)

• Seer Interactive — Data-driven, enterprise-oriented SEO and analytics; good for large B2B sites needing measurement + insights. (beomniscient.com)
• Ten or so other reputable options frequently recommended in 2024–2025 roundups: Grow & Convert, Directive (also does web dev integrations), Siege Media (content + dev handoffs), and smaller specialist shops (Link-Assistant roundup of top B2B SEO agencies). (alexbirkett.com)

How to pick among these

• If you’re enterprise / technical product: prioritize agencies strong in technical SEO and analytics (iPullRank, Seer, Omniscient). (beomniscient.com)
• If you need content-driven lead gen: pick content+link specialists (Siege Media, Ten Speed, RevenueZen). (Link-Assistant.com)
• If you need a combined website redesign + acquisition program: choose full-service firms that build and then optimize (WebFX, SmartSites, KlientBoost). (onelittleweb.com)

Want this tailored to your situation? If you share your company size (startup, scale-up, enterprise), primary vertical (SaaS, manufacturing, services), annual digital marketing budget, and whether you already have dev resources in-house, I can:

• shortlist 3–5 agencies best-matched to your needs and budget, and
• provide suggested brief/email template and RFP checklist to evaluate proposals.

If you prefer, I can also produce a downloadable comparison (pricing ranges, team size, notable B2B clients) for the top 6 agencies above.