Update README.md

Updating Arize AX descriptions and value ads.

README.md

@@ -226,7 +226,7 @@ This list results from Pull Requests, reviews, ideas, and work done by 1600+ peo
   * [Apify](https://www.apify.com/) - Web scraping and automation platform to create an API for any website and extract data. Ready-made scrapers, integrated proxies, and custom solutions. Free plan with $5 platform credits included every month.
   * [APITemplate.io](https://apitemplate.io) - Auto-generate images and PDF documents with a simple API or automation tools like Zapier & Airtable. No CSS/HTML is required. The free plan comes with 50 images/month and three templates.
   * [APIVerve](https://apiverve.com) - Get instant access to over 120+ APIs for free, built with quality, consistency, and reliability in mind. The free plan covers up to 50 API Tokens per month. (Possibly taken down, 2025-06-25)
-  * [Arize AI](https://arize.com/) - Machine learning observability for model monitoring and root-causing issues such as data quality and performance drift. Free up to two models.
+  * [Arize AI](https://arize.com/) - AI observability and evaluation platform that helps teams understand, evaluate, and continuously improve AI agents and applications. Free to get started.
   * [Beeceptor](https://beeceptor.com) - No-code, cloud-based platform for mocking and debugging multi-protocol APIs (REST, SOAP, gRPC & GraphQL), providing instant servers with rules-based logic, CRUD & stateful mocking, proxying, and CORS management for faster integration and testing. The free plan includes 50 requests per day and provides a public dashboard/endpoint where anyone with the dashboard URL can view submitted requests and responses.
   * [BigDataCloud](https://www.bigdatacloud.com/) - Provides fast, accurate, and free (Unlimited or up to 10K-50K/month) APIs for modern web like IP Geolocation, Reverse Geocoding, Networking Insights, Email and Phone Validation, Client Info and more.
   * [Brave Search API](https://brave.com/search/api/) - Independent web, news, image, video search and AI/LLM context API, suitable for RAG pipelines and AI agents. Free tier includes $5 in monthly credits (credit card required for verification).
@@ -1025,7 +1025,7 @@ This list results from Pull Requests, reviews, ideas, and work done by 1600+ peo
 
 ## Generative AI
 
-  * [Arize AX](https://arize.com) - AI engineering platform that helps AI eng/PMs, evaluate, and observe AI applications and agents with built-in Alyx agent. Free product includes 25k spans and ingestion volume of 1gb per month.
+  * [Arize AX](https://arize.com) - AI engineering platform that helps AI eng/PMs, evaluate, and observe AI applications and agents with built-in Alyx agent. Free product includes unlimited users and evals, 25k spans, 10 free Signals (always-on SRE agent that finds and fixes issues in production), ingestion volume of 1gb per month. Arize Phoenix as an open source option.
   * [Audio Enhancer](https://voice-clone.org/tools/audio-enhancer) - AI-powered audio enhancer SaaS that removes noise and echo while preserving natural vocal clarity. totally Free: unlimited one-click enhancements, no login required, supports MP3/WAV/FLAC
   * [Braintrust](https://www.braintrustdata.com/) - Evals, prompt playground, and data management for Gen AI. Free plan gives upto 1,000 private eval rows/week.
   * [Clair](https://askclair.ai/) - Clinical AI Reference. Students have free access to the professional tool suite, which includes Open Search, Clinical Summary, Med Review, Drug Interactions, ICD-10 Codes, and Stewardship. Additionally, a free trial for the professional suite is available.