Blessings of objects by the Priest

Kind of reminds me of a scene from Fiddler on the Roof where they asked the Rabbi for a blessing for a sewing machine and he just made one up on the spot.

Anything that is a sacramental (Rosary, Crucifix, Scapular, etc...) will have prayers of blessing. People too have formalized blessings that I believe are usually approved by a particular Bishop and then promulgated for common use; these are prayers for soldiers, pregnant mothers and other glorious professions. Places, like new homes and offices have formal prayers and these can all be found in good books like the Handbook of Prayers. But, I'd imagine that a good priest, like the Rabbi of anatevk, would be able to come up with a blessing for your thing, so long as it had a good purpose.

You cant in good conscious name your kids beezlebul and expect them to get Baptized with that name, for the same reason l, you'd probably have a hard time getting a priest to bless something bought at a smut shop. But you might be able to get a blessing for a pack of cigarettes or a bottle of wine or a gun or something since they don't have an objectively nefarious purpose.

But speaking purely on conjecture and not assuming that because I've never read this in any of my Catechetical texts that there is no list. I'm pretty sure scapulars are the only things laypeople really need to have blessed, because the blessing iis accompanied with a promise. I suppose the same would go for a person want to be in the Militia Immaculata, they would want to wear a blessed Miraculous Medal. And if you were in the confreternity of the most holy rosary, you would want to pray a blessed Rosary (but that's a good idea even if you're not a member).

Basically, if the Church considers it to be a Sacramental, then it should be blessed. But there are other things like Christmas Trees which I don't believe are considered sacramentals that can be blessed.

There is no list of items that "must" be blest by a priest (or a deacon), yet we Catholics are used to blessing everything. There are items that can be required to be blest by a certain person. The crucifix of St. Benedict is required to be blest by a deacon or priest. There really isn't a source of which I am aware one can go to to find this kind of answer, but the catechism addresses it more in terms of general principles. See CCC Chapter 4, Article 1, paragraphs 1667-1679.

In terms of blessing sacramentals, this is the general principle from the catechism:

Sacramentals derive from the baptismal priesthood: every baptized person is called to be a “blessing,” and to bless. [Cf. Gen 12:2; Lk 6:28; Rom 12:14; 1 Pet 3:9.] Hence lay people may preside at certain blessings; the more a blessing concerns ecclesial and sacramental life, the more is its administration reserved to the ordained ministry (bishops, priests, or deacons). [Cf. SC 79; CIC, can. 1168; De Ben 16, 18.]

CCC 1669

Further, Canon Law states:

The minister of the sacramentals is a cleric who has the requisite power. In accordance with the liturgical books and subject to the judgment of the local Ordinary, certain sacramentals can also be administered by lay people who possess the appropriate qualities.

Canon 1168

The forms of sacramentals described in 1670 is expressed this way, "Among sacramentals blessings (of persons, meals, objects, and places) come first."

From this it is clear that liturgical and sacramental blessings require a deacon or priest. It also implies ordinary Christians can bless outside sacramental and ecclesial (church) life (except in the case of solemn or major exorcism, see 1673). It would be advisable for a Catholic to consult the parish priest or diocesan bishop concerning this to avoid dangers or going too far with it.