1955 proposed locations for Interstate Highways
Map of proposed locations for Interstates in San Antonio from the Bureau of Public Road's "General Location of National System of Interstate Highways" publication, also known as the "Yellow Book" because of its yellow cover. Published in 1955, it was essentially the blueprint for the Interstate Highway System. You'll notice the proposed routing for I-10 East-- roughly the Commerce St.corridor. However, I think this was more likely a placeholder as I have found no local plans that considered that routing. Also note the proposed route for I-10 West was along Fredericksburg Rd.; this is likely also a placeholder as I have found no local plans that considered Fredericksburg Rd. for I-10. Finally, note the omission of the northern stretch of Loop 410-- it was not included in the original Interstate plans due to a disagreement between state and federal officials about design standards along that stretch, much of which was a pre-existing stretch of Loop 13.
(wikisource.org)

1956 expressway plan
This was the first plan for a comprehensive citywide freeway system and the first proposal for what would become Loop 1604. Also note the proposals for expressways along Bandera Rd., Roosevelt Ave., and Zarzamora St.
(TxDOT)

1964 expressway plan
Note the connectors from US 281 to Loop 410 along San Pedro and from US 281 to I-35 along St. Mary's as well as the updated Bandera Freeway proposal.
(SABCUTS)

1975 expressway plan
This shows the final iteration of the Bandera Freeway along Culebra before it was cancelled.
(SABCUTS)

Proposed I-10 (US 87) and Culebra interchange (1945)
(TxDOT)

Proposed routing for I-10 (US 87) from Hildebrand Ave. to Fredericksburg Rd. (1953)
This was the first proposal to route I-10 West. It would have run significantly further east than the eventual alighment.
(Due to the size of this image, it will open in a separate window that you can scroll and zoom.)
(TxDOT)

Proposed interchange for US 90 and I-35 (1953)
This was the first proposal for the US 90 expressway. It would have run substantially further north than the eventual alignment, generally following Guadalupe St. through the West Side and crossing I-35 (US 81) at El Paso St. Notice that this would have only been a three-level interchange.
(TxDOT)

Proposed routing for US 90 through King William (1953)
Continuing east from the interchange at I-35, the proposed US 90 expressway would have sliced through King William and Southtown between Beauregard St. and Sheridan St. Heading east, it would have crossed I-37 at Indiana St. and followed the Indiana St. and Aransas Ave. corridors through the East Side.
(TxDOT)

Proposed Fratt Interchange (I-35/Loop 410 NE) (ca. 1954)
This was the first proposal for the Fratt Interchange. This plan also shows that the initial proposed route for I-35 north of the interchange was along Randolph Blvd.
(Due to the size of this image, it will open in a separate window that you can scroll and zoom.)
(TxDOT)

Proposed US 281/St. Mary's Connection interchange (1964)
(SABCUTS)

Proposed US 281/Loop 410 interchange (1964)
This interchange was never built due to escalating costs after the freeway was delayed by lawsuits for a decade.
(SABCUTS)

Proposed Bandera Freeway interchanges (1964)
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Proposed downtown distribution system (1964)
This was a plan for an intricate system of entrance and exit ramps along the downtown freeways. Most of the ramps were never built as proposed. The numbers on the map were projected traffic volumes.
(SABCUTS)