feat: add RareSkills Proxy Patterns and SolidState to Upgradeable Contracts

[mnusurov]

Resource Addition/Update

Resource Information

1. RareSkills Book of Proxy Patterns

• Name: RareSkills Book of Proxy Patterns
• URL: https://rareskills.io/proxy-patterns
• Category: Upgradeable Contracts

2. SolidState Solidity

• Name: SolidState Solidity
• URL: https://github.com/solidstate-network/solidstate-solidity
• Category: Upgradeable Contracts

Description

1. Comprehensive guide to proxy patterns including UUPS, Transparent, Beacon, and Diamond proxies with upgrade safety considerations.
2. Upgradeable-first smart contract library built around EIP-2535 Diamond facets and proxy patterns.

Why should this be added?

The Upgradeable Contracts section had not been substantively updated since May 2026 and contained only two entries. The section was the most stale in the list:

• RareSkills Proxy Patterns fills the learning-guide gap — the section had tooling docs (OpenZeppelin Upgrades) and a resource list (Awesome Diamonds), but no comprehensive educational material on proxy patterns. Published by RareSkills, already a trusted source in this list (Gas Optimization guide).
• SolidState Solidity (471 stars, 96 forks, last commit 2026-06-13) is an upgradeable-first contract library — unique positioning vs. OpenZeppelin Contracts (not upgradeable-first) and Awesome Diamonds (a list, not a library). Confirmed listed in the sister list bkrem/awesome-solidity.

Also fixes pre-existing alphabetical ordering issue in the section (Awesome Diamonds was listed after OpenZeppelin: Upgrades).

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Checklist

• I've searched for duplicates using GitHub search and existing issues
• The resource is primarily in English (or has an English version)
• The resource is free or clearly marks paid sections
• The resource focuses specifically on Solidity (not general blockchain/Web3)
• Description is concise and neutral (no promotional language)
• Grammar and spelling have been verified (using a tool or manual check)
• Links are working and point to the correct content
• The resource is actively maintained (if applicable)

Additional Context

Candidates vetted via the find-resources scouting process: GitHub search (100+ stars / commit within 3 months filter), web search, and a sweep of all pre-vetted sources (Trail of Bits blog, Cyfrin blog, sister list, Cantina). SolidState confirmed via two independent discovery paths. Rejected near-misses: prb-proxy (niche personal account proxy), Perfect-Abstractions/Compose (111 stars, barely clears bar), EIP-2535/ERC-1167 links (near-dupes of the existing EIPs entry), Trail of Bits upgrade anti-patterns (2018, dated).

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