8GB (2x4GB) MEMORY RAM FOR IBM Lenovo ThinkPad T61, T61p DDR2 PC5300 SODIMM | eBay
CMS 8GB (2X4GB) DDR2 5300 667MHZ Non ECC SODIMM Memory Ram Upgrade Compatible with IBM Lenovo® Thinkpad T61, T61P Ddr2 Pc5300 Sodimm - B116 at Amazon.com
Lenovo Thinkpad T61 RAM-Memory (2 Gig) | Replacement Part
2GB Memory RAM Upgrade for the Lenovo Thinkpad R61 Series, T60 Series, T61 Series, X60 Series and X61 Series Laptops (DDR2-667, PC2-5300, SODIMM) at Amazon.com
OFFTEK 2GB Replacement Memory RAM Upgrade for IBM-Lenovo ThinkPad T61 (7665-xxx) (DDR2-5300) Laptop Memory at Amazon.com
IBM Thinkpad T61 RAM Replacement - iFixit Repair Guide
IBM Lenovo ThinkPad T61 14" T8100 2.00GHz 2GB RAM 500GB HDD (1440 x 900) MR25-10 | eBay
I “think” you enjoy this… T61 (256 Gb SSD Debian 10, RAM 4 Gb) and E14 2021 (upgrade with RAM 16 Gb, 1 Tb M.2 for Windows 11 and 256 Gb SSD for Debian 11, all Crucial) : r/thinkpad