| Affix |
| Annex |
| Wing. |
| Extra |
| Rider |
| Append |
| Expand |
| Attach |
| Suffix |
| Extend |
| New wing |
| Lengthen |
| Any annex |
| Extra bit |
| Expansion |
| Accessory |
| ___ bonus |
| Supplement |
| Extension. |
| Peripheral |
| Extend with |
| Enlargement |
| Rider, e.g. |
| Enhancement |
| Not standard |
| Write a P.S. |
| Attach(ment) |
| Building wing |
| Attach an ell |
| Accompaniment |
| Extra feature |
| Build an annex |
| Extra purchase |
| Many a toolbar |
| Home extension |
| Building annex |
| Garage, perhaps |
| Surcharge, e.g. |
| Write a codicil |
| Enlarge a house |
| Contribute (to) |
| Extra-cost item |
| House extension |
| Something extra |
| Build a new room |
| Home improvement |
| Software plug-in |
| Aftermarket item |
| ___ extra charge |
| Increase stitches |
| Auto option, e.g. |
| Attach at the end |
| Enlarge the house |
| Peripheral device |
| After-market item |
| Enlarge as a room |
| Optional component |
| Software accessory |
| Supplementary item |
| Include as a bonus |
| Something attached |
| Computer accessory |
| Building wing, e.g. |
| Aftermarket purchase |
| After-market purchase |
| Build a new wing, say |
| Build a new room, say |
| Supplementary feature |
| Enlarge the house, say |
| Supplemental component |
| Residence afterthought |
| Browser extension, e.g. |
| Firefox extension, e.g. |
| Legislative rider, e.g. |
| Architect's afterthought |
| Build an extra room, say |
| Computer peripheral, say |
| Computer accessory: Hyph. |
| Computer peripheral, e.g. |
| Something attached: Hyph. |
| Building contractor's job |
| Architectural afterthought |
| Attach, as a building wing |
| Cramped handyman's project |
| Home builder's afterthought |
| Home improvement, of a sort |
| Extra, and this puzzle's title |
| New wing of a building, say: Hyph. |