Aldermore has expanded lending criteria, while Keystone Property Finance and Kent Reliance have adjusted selected mortgage rates.
Aldermore will now consider ex-local authority flats with open balcony or deck access, provided there is secure ground-floor access.
It will also consider owner-occupied properties with cladding requiring remediation and a B2 rating, as well as properties on the Scottish Islands.
The lender has increased its maximum single-unit buy-to-let property value to £3m in London and the South East and £2m across the rest of the UK.
The changes take effect today.
Meanwhile, Keystone has increased fixed rates across its standard buy-to-let, Holiday Let, Product Transfer, Product Transfer Plus and Refurb Exit ranges by 10 basis points (bps).
However, rates for houses in multiple occupation and multi-units with between seven and 20 occupants or units have been cut by 5bps.
Ex-pat rates have also been reduced by 10bps.
The changes are available from today.
Kent Reliance for Intermediaries is also increasing rates across its buy-to-let and residential product transfer ranges.
Current products will be withdrawn at 5pm today.
The new higher-rate product transfer ranges will become available tomorrow.
Newcastle for Intermediaries has also withdrawn a number of products today.